Runing :

Teamspeak 3 [3.0.0-rc1-pre11 [Build: 13907] ]
Firefox 3
KeyPass
WinScp
Zscreen
Notepad ++
In notepad ++ add new tab (crtl + n) then error.

Code:
Assertion chatTab failed at client\clientui\UI_qt\chattabwidget.cpp:154;
also many warnings like below
Code:
2011-04-05 22:23:03.328125|WARNING |Direct Sound  |   | RenderDeviceContext::int_processData slept for 49 msecs

Code:
Microsoft Windows XP Professional 5.1.2600 Service Pack 3 
Common Controls  	6.00
Internet Explorer  	8.0.6001.18702
Outlook Express  	6.00.2900.5512 (xpsp.080413-2105)
Windows Media Player  	11.0.5721.5145 (WMP_11.061018-2006)
DirectX  	4.09.00.0904 (DirectX 9.0)
OpenGL  	5.1.2600.5512 (xpsp.080413-0845)