Version:           3.5.2 (using KDE 3.5.2, Kubuntu Package 4:3.5.2-0ubuntu18 dapper)
Compiler:          Target: i486-linux-gnu
OS:                Linux (i686) release 2.6.15-23-k7

I was type a new mail in Kontact/Kmail... I then change the spellcheck language (from french (defautl) to english). I had a message box saying that the dialog had to reload... the Kontact/Kmail crashes! I tried to relaunch Kontact, crash again just after starting.
So I tried to run Kmail (alone, without Kontact) from Konsole and here the "log":

user@eddy:~/tmp$ kmail
X Error: BadDevice, invalid or uninitialized input device 168
  Major opcode:  148
  Minor opcode:  3
  Resource id:  0x0
Failed to open device
X Error: BadDevice, invalid or uninitialized input device 168
  Major opcode:  148
  Minor opcode:  3
  Resource id:  0x0
Failed to open device
kmail: WARNING: [void KMFolderImap::setImapPath(const QString&)] ignoring empty path
ScimInputContextPlugin()
QWidget::setMaximumSize: (unnamed/RecipientComboBox) The largest allowed size is (32767,32767)
WeaverThreadLogger: thread (ID: 1) suspended.
WeaverThreadLogger: thread (ID: 2) suspended.
WeaverThreadLogger: thread (ID: 3) suspended.
WeaverThreadLogger: thread (ID: 4) suspended.
kdecore (KAction): WARNING: KAction::plugAccel(): call to deprecated action.
kdecore (KAction): WARNING: KAction::plugAccel( kacc = 0x8311e48 ): KAccel object already contains an action name "delete"
kdecore (KAction): WARNING: KAction::plugAccel(): call to deprecated action.
kdecore (KAction): WARNING: KAction::plugAccel( kacc = 0x8311e48 ): KAccel object already contains an action name "edit"
kdecore (KAction): WARNING: KAction::plugAccel(): call to deprecated action.
kdecore (KAction): WARNING: KAction::plugAccel( kacc = 0x8311e48 ): KAccel object already contains an action name "display_message"
user@eddy:~/tmp$ *** KMail got signal 11 (Crashing)
KCrash: Application 'kmail' crashing...