Version:           1.4.1 (using KDE KDE 3.4.2)
Installed from:    Gentoo Packages
Compiler:          gcc 3.4.4  (Gentoo 3.4.4-r1, ssp-3.4.4-1.0, pie-8.7.8)
OS:                Linux

Kword crashes either just after starting, when the document window becomes focus or also after a short time (minutes) after start in a apparently random way.

NOTE: This bug is resolved, just posted for the sake of informing other users and devs (it's a silly one indeed).

Here's a backtrace for your info:

=======================================================
no debugging symbols found)
Using host libthread_db library "/lib/libthread_db.so.1".
(no debugging symbols found)
...
0xffffe410 in ?? ()
#0  0xffffe410 in ?? ()
#1  0x00001b63 in ?? ()
#2  0x00000000 in ?? ()
#3  0x00000000 in ?? ()
#4  0xb6b063a3 in waitpid () from /lib/libpthread.so.0
#5  0xb7804669 in KCrash::defaultCrashHandler ()
   from /usr/kde/3.4/lib/libkdecore.so.4
#6  0x00000002 in ?? ()
#7  0xbfffcdc8 in ?? ()
#8  0xbfffcdcc in ?? ()
#9  0x00000006 in ?? ()
#10 0x00000000 in ?? ()
#11 0x00002e30 in ?? ()
#12 0xb74d5fe0 in typeinfo name for QLibrary ()
   from /usr/qt/3/lib/libqt-mt.so.3
#13 0x00000000 in ?? ()
#14 0x037f0c7f in ?? ()
#15 0x00001b63 in ?? ()
#16 0x00000400 in ?? ()
#17 0x00000400 in ?? ()
#18 0xb69d8820 in __malloc_initialize_hook () from /lib/libc.so.6
#19 0x083a6628 in ?? ()
#20 0xbfffcd38 in ?? ()
#21 0xb6925cf9 in free () from /lib/libc.so.6
===========================================================================

SOLVING:

The bug is caused by stale .aspell and .ispell files such as personal dictionaries from older spellchecker installations. Just removing them makes everything run fine again. 
(There are ways to restore or merge spelling dictionaries).