this is server issue, it happends. 
please report to sms express, not to me.

Works perfectly ok for other clients, for example gg2.

Of course it works with others, like kadu and gg2. I don't know what with gaim,
haven't tested. As for complaining to sms express: 
1) GG regulations forbids using other clients than original GG;
2) All mail to GG is directed to /dev/null, they never answer.

> this is server issue, it happends. 
> please report to sms express, not to me. 

No, this is kopete gg plugin issue. I've tested other clients and only kopete ignores "offline messages".

Please recompile gadu plugin with debuging enabled, in  
gadusession.cpp there is variable you have to uncoment first to get  
much more debuging info, and check yourself if kopete is really  
discarding those mesgs. I doubt it. Can't see it here.

Of course Kopete is discarding those offline messages. I recompiled Kopete with
debugs enables as you said. I disconnected with gg and asked my friend to send
me 6 messages while I was offline. Then I connected with gg, and this is the
output (a bit long, but I wanted to show full debug):

--- cut here ---
** gg_create_dcc_socket(-1, 1550);
// gg_create_dcc_socket() trying port 1550
// gg_create_dcc_socket() bound to port 1550
** gg_login(0x82f00dc: [uin=3562330, async=1, ...]);
** gg_resolve_pthread(0x94215b8, 0x9421644, "appmsg.gadu-gadu.pl");
// gg_resolve_pthread() 0x8cfd1a8
** gg_watch_fd(0x94215b8);
// gg_watch_fd() GG_STATE_RESOLVING
// gg_watch_fd() resolved, connecting to 217.17.46.251:80
** gg_connect(217.17.46.251, 80, 1);
// gg_connect() connect() in progress
** gg_event_free(0x8cae1a0);
** gg_watch_fd(0x94215b8);
// gg_watch_fd() GG_STATE_CONNECTING_HUB
// gg_watch_fd() connected to hub, sending query
=> -----BEGIN-HTTP-QUERY-----
GET /appsvc/appmsg2.asp?fmnumber=3562330&version=6%2c+0%2c+0%2c+132&lastmsg=0
HTTP/1.0
Host: appmsg.gadu-gadu.pl
User-Agent: Mozilla/4.7 [en] (Win98; I)
Pragma: no-cache


=> -----END-HTTP-QUERY-----
** gg_event_free(0x94264c0);
** gg_watch_fd(0x94215b8);
// gg_watch_fd() GG_STATE_READING_DATA
** gg_connect(217.17.41.93, 8074, 1);
// gg_connect() connect() in progress
** gg_event_free(0x904fa10);
** gg_watch_fd(0x94215b8);
// gg_watch_fd() GG_STATE_CONNECTING_GG
// gg_watch_fd() connected
** gg_event_free(0x8cb6860);
** gg_watch_fd(0x94215b8);
// gg_watch_fd() GG_STATE_READING_KEY
** gg_recv_packet(0x94215b8);
// gg_recv_packet() header recv(17,0xbfffdd00,8) = 8
// gg_recv_packet() body recv(17,0x8cda210,4) = 4
// gg_watch_fd() gg_dcc_ip = 255.255.255.255
// gg_watch_fd() detecting address
// gg_watch_fd() detected address to 213.155.177.2
** gg_send_packet(0x94215b8, 0x15, ...)
** gg_event_free(0x82ef0c8);
** gg_watch_fd(0x94215b8);
// gg_watch_fd() GG_STATE_READING_REPLY
** gg_recv_packet(0x94215b8);
// gg_recv_packet() header recv(17,0xbfffdd00,8) = 8
// gg_watch_fd() login succeded
** gg_notify(0x94215b8, 0x8cb0d78, 97);
** gg_send_packet(0x94215b8, 0x10, ...)
** gg_send_packet(0x94215b8, 0x16, ...)
** gg_event_free(0x94213c0);
** gg_watch_fd(0x94215b8);
// gg_watch_fd() GG_STATE_CONNECTED
** gg_watch_fd_connected(0x94215b8, 0x8f8f760);
** gg_recv_packet(0x94215b8);
// gg_recv_packet() header recv(17,0xbfffdca0,8) = 8
// gg_recv_packet() body recv(17,0x943bb10,1969) = 1969
// gg_watch_fd_connected() received a notify reply
** gg_event_free(0x8f8f760);
** gg_watch_fd(0x94215b8);
// gg_watch_fd() GG_STATE_CONNECTED
** gg_watch_fd_connected(0x94215b8, 0x8f79bd8);
** gg_recv_packet(0x94215b8);
// gg_recv_packet() header recv(17,0xbfffdca0,8) = 8
// gg_recv_packet() body recv(17,0x830a090,46) = 46
** gg_handle_recv_msg(0x830a088, 0x8f79bd8);
** gg_event_free(0x8f79bd8);
** gg_watch_fd(0x94215b8);
// gg_watch_fd() GG_STATE_CONNECTED
** gg_watch_fd_connected(0x94215b8, 0x941eb30);
** gg_recv_packet(0x94215b8);
// gg_recv_packet() header recv(17,0xbfffdca0,8) = 8
// gg_recv_packet() body recv(17,0x84df488,35) = 35
** gg_handle_recv_msg(0x84df480, 0x941eb30);
** gg_event_free(0x941eb30);
** gg_watch_fd(0x94215b8);
// gg_watch_fd() GG_STATE_CONNECTED
** gg_watch_fd_connected(0x94215b8, 0x941eb30);
** gg_recv_packet(0x94215b8);
// gg_recv_packet() header recv(17,0xbfffdca0,8) = 8
// gg_recv_packet() body recv(17,0x8f555b0,41) = 41
** gg_handle_recv_msg(0x8f555a8, 0x941eb30);
** gg_event_free(0x941eb30);
** gg_watch_fd(0x94215b8);
// gg_watch_fd() GG_STATE_CONNECTED
** gg_watch_fd_connected(0x94215b8, 0x941eb30);
** gg_recv_packet(0x94215b8);
// gg_recv_packet() header recv(17,0xbfffdca0,8) = 8
// gg_recv_packet() body recv(17,0x8f91610,20) = 20
** gg_handle_recv_msg(0x8f91608, 0x941eb30);
** gg_event_free(0x941eb30);
** gg_watch_fd(0x94215b8);
// gg_watch_fd() GG_STATE_CONNECTED
** gg_watch_fd_connected(0x94215b8, 0x941eb30);
** gg_recv_packet(0x94215b8);
// gg_recv_packet() header recv(17,0xbfffdca0,8) = 8
// gg_recv_packet() body recv(17,0x84df488,33) = 33
** gg_handle_recv_msg(0x84df480, 0x941eb30);
** gg_event_free(0x941eb30);
** gg_watch_fd(0x94215b8);
// gg_watch_fd() GG_STATE_CONNECTED
** gg_watch_fd_connected(0x94215b8, 0x941eb30);
** gg_recv_packet(0x94215b8);
// gg_recv_packet() header recv(17,0xbfffdca0,8) = 8
// gg_recv_packet() body recv(17,0x84df488,30) = 30
** gg_handle_recv_msg(0x84df480, 0x941eb30);
** gg_event_free(0x941eb30);
** gg_watch_fd(0x94215b8);
// gg_watch_fd() GG_STATE_CONNECTED
** gg_watch_fd_connected(0x94215b8, 0x8f8f490);
** gg_recv_packet(0x94215b8);
// gg_recv_packet() header recv(17,0xbfffdca0,8) = 8
// gg_recv_packet() body recv(17,0x9438670,2010) = 2010
// gg_watch_fd_connected() received userlist reply
userlist_reply=(nil), len=0
** gg_event_free(0x8f8f490);
--- cut here ---

As you can see, there are 6 "gg_handle_recv_msg", which are ignored and not
shown by Kopete. Is this still SMS Express issue?

don't be so rude. If you demand something, pay. Or shut up and be polite. 
Reason why I asked (not fucking demanded) to turn this debug option on, is to 
see whether your problem is on our side, or theirs. So shut the fuck up, and 
follow my next instructions, as they arrive as soon as I will check the 
issue.

Next time you will be rude, I'll give you my account number, and won't do 
anything unless you pay. This is opensource for ****** sake. Get yourself 
windows machine with proprietary gadu client if you don't like it.

SVN commit 461125 by gj:

BUG:105131
message class is a bitfield, so and for flags, do not just match up.
Note to packagers, please backport to all possible releases. This is a serious bug fix. 



 M  +1 -1      gaduaccount.cpp  
 M  +3 -3      gadusession.cpp  


--- branches/KDE/3.5/kdenetwork/kopete/protocols/gadu/gaduaccount.cpp #461124:461125
@@ -157,8 +157,8 @@
 
 	p->config = configGroup();
 
+	initConnections();
 	initActions();
-	initConnections();
 
 	QString nick = p->config->readEntry( QString::fromAscii( "nickName" ) );
 	if ( !nick.isNull() ) {
--- branches/KDE/3.5/kdenetwork/kopete/protocols/gadu/gadusession.cpp #461124:461125
@@ -704,20 +704,20 @@
 
 	switch( event->type ) {
 		case GG_EVENT_MSG:
+			kdDebug(14100) << "incoming message:class:" << event->event.msg.msgclass << endl;
 			if ( event->event.msg.msgclass == GG_CLASS_CTCP ) {
 				kdDebug( 14100 ) << "incomming ctcp " << endl;
 				// TODO: DCC CONNECTION
 				emit incomingCtcp( event->event.msg.sender );
-				break;
 			}
-			if ( event->event.msg.msgclass == GG_CLASS_MSG || event->event.msg.msgclass == GG_CLASS_CHAT ) {
+
+			if ( (event->event.msg.msgclass & GG_CLASS_MSG) || (event->event.msg.msgclass & GG_CLASS_CHAT) ) {
 				gaduMessage.message =
 					textcodec->toUnicode((const char*)event->event.msg.message);
 				gaduMessage.sender_id = event->event.msg.sender;
 				gaduMessage.sendTime.setTime_t( event->event.msg.time, Qt::LocalTime );
 				gaduMessage.message = rtf->convertToHtml( gaduMessage.message, event->event.msg.formats_length, event->event.msg.formats );
 				emit messageReceived( &gaduMessage );
-				break;
 			}
 		break;
 		case GG_EVENT_ACK:

Sorry dude, I won't pay you anything, cause I employ only good developers.

pay attention to yer words, I am already being paid to work on opensource. And 
I am a good developer. And you're just bloody kid. So shut you. (and learn 
English).

shut yer wanking mouth, that is. (already had too much Johnnie W.)

just like in other bug-reports the only rude person is  Mr. perfect=Grzegorz
Jaskiewicz 

*** Bug 112543 has been marked as a duplicate of this bug. ***