Crash after AfxMessageBox call

in my Win32 application (using Windows2000, VC 6, GeForce2) the programm crashes in debug- and release mode after trying to call an AfxMessageBox - but only “sometimes”. The GraphicsView uses OpenGL drawing, it’s working well - except of message boxes.

e.g.: After program start I load a bad document causing an AxfMessageBox call in the loadDocument routine … the box doesn’t appear and the programm crashes with:
“Unhandled exception in myProg.exe: 0xC0000005. Access violation”.

The call stack finds at the first OpenGL-command in the GraphicsView:OnDraw() tree.

It seems to be a rendering or device context switching problem …? Any comments are highly welcome!!

Many thanks