We need a better stacktrace. Please read http://techbase.kde.org/Development/Tutorials/Debugging/How_to_create_useful_crash_reports and reopen after following the steps in that document and providing another backtrace.

Program: Kopete (kopete), sygnał SIGSEGV
[Thread debugging using libthread_db enabled]
[New Thread 0xb56796d0 (LWP 9320)]
[KCrash handler]
#6  0xb354ece4 in GaduContact::uin (this=0x0)
    at /usr/src/debug/kdenetwork-4.1.2/kopete/protocols/gadu/gaducontact.cpp:88
#7  0xb3557935 in GaduAccount::userlist (this=0x91dd3f8)
    at /usr/src/debug/kdenetwork-4.1.2/kopete/protocols/gadu/gaduaccount.cpp:1083
#8  0xb3557a22 in GaduAccount::slotExportContactsList (this=0x91dd3f8)
    at /usr/src/debug/kdenetwork-4.1.2/kopete/protocols/gadu/gaduaccount.cpp:1065
#9  0xb355d460 in GaduAccount::qt_metacall (this=0x91dd3f8, 
    _c=QMetaObject::InvokeMetaMethod, _id=49, _a=0xbfc6a8a8)
    at /usr/src/debug/kdenetwork-4.1.2/build/kopete/protocols/gadu/gaduaccount.moc:224
#10 0xb7484c8d in QMetaObject::activate (sender=0x9320710, 
    from_signal_index=4, to_signal_index=4, argv=0x0)
    at kernel/qobject.cpp:3031
#11 0xb7485a95 in QMetaObject::activate (sender=0x9320710, m=0xb7556ce4, 
    local_signal_index=0, argv=0x0) at kernel/qobject.cpp:3101
#12 0xb74c0ef5 in QTimer::timeout (this=0x9320710)
    at .moc/release-shared/moc_qtimer.cpp:126
#13 0xb748b946 in QTimer::timerEvent (this=0x9320710, e=0xbfc6ad1c)
    at kernel/qtimer.cpp:257
#14 0xb747f51b in QObject::event (this=0x9320710, e=0xbfc6ad1c)
    at kernel/qobject.cpp:1120
#15 0xb6910fac in QApplicationPrivate::notify_helper (this=0x9080210, 
    receiver=0x9320710, e=0xbfc6ad1c) at kernel/qapplication.cpp:3803
#16 0xb6919205 in QApplication::notify (this=0xbfc6af9c, receiver=0x9320710, 
    e=0xbfc6ad1c) at kernel/qapplication.cpp:3393
#17 0xb79ae771 in KApplication::notify () from /usr/lib/libkdeui.so.5
#18 0xb746f853 in QCoreApplication::notifyInternal (this=0xbfc6af9c, 
    receiver=0x9320710, event=0xbfc6ad1c) at kernel/qcoreapplication.cpp:587
#19 0xb749ea8d in QTimerInfoList::activateTimers (this=0x9086ad4)
    at kernel/qcoreapplication.h:209
#20 0xb749b3ee in timerSourceDispatch (source=0x9086aa0)
    at kernel/qeventdispatcher_glib.cpp:160
#21 0xb5d2c7ca in IA__g_main_context_dispatch (context=0x9085e60)
    at gmain.c:2142
#22 0xb5d2fee8 in g_main_context_iterate (context=0x9085e60, block=1, 
    dispatch=1, self=0x9081da8) at gmain.c:2776
#23 0xb5d300a8 in IA__g_main_context_iteration (context=0x9085e60, 
    may_block=1) at gmain.c:2839
#24 0xb749b34a in QEventDispatcherGlib::processEvents (this=0x9083be8, flags=
      {i = -1077498232}) at kernel/qeventdispatcher_glib.cpp:319
#25 0xb69ad95a in QGuiEventDispatcherGlib::processEvents (this=0x9083be8, 
    flags={i = -1077498184}) at kernel/qguieventdispatcher_glib.cpp:198
#26 0xb746dec3 in QEventLoop::processEvents (this=0xbfc6af30, flags=
      {i = -1077498120}) at kernel/qeventloop.cpp:143
#27 0xb746e081 in QEventLoop::exec (this=0xbfc6af30, flags={i = -1077498056})
    at kernel/qeventloop.cpp:194
#28 0xb74707f2 in QCoreApplication::exec () at kernel/qcoreapplication.cpp:845
#29 0xb6910e14 in QApplication::exec () at kernel/qapplication.cpp:3331
#30 0x08087f95 in main (argc=-1077496956, argv=0xbfc6afbc)
    at /usr/src/debug/kdenetwork-4.1.2/kopete/kopete/main.cpp:102

Hi Darek, could you explain me our setup in details. I've tried to reproduce the crash in Kopete 0.70.2 (KDE 4.2.2) and it worked just fine.
My setup were:

Case one:
Default identity
 -my main gg account
 -test gg account
 -my msn account

Case two:
Default identity
 -my main gg account
 -my msn account
Testy identity
  -test gg account

In both cases Kopete connected to all accounts with no problem.
Can you reproduce the crash with new version of Kopete?

I've checked. In version 0.60.3 the problem is solved.