As the assertion is related to a CString object, the code snippet you've provided is of no help. You'll need to locate the CString object in question. Given that m_pchData is in error, my first guess is that it is a heap-based object. "Opinions are neither right nor wrong. I cannot change your opinion. I can, however, change what influences your opinion." - David Crow

Kapgan wrote: I included the .h file in MainFrm.cpp. Put it in the MainFrm.h file. Why aren't you extending CToolBar? ed ~"Watch your thoughts; they become your words. Watch your words they become your actions. Watch your actions; they become your habits. Watch your habits; they become your character. Watch your character; it becomes your destiny." - -Uknown.

Thanks guys.:)