Fail to SetAt for CMap, Clist class

Dear all,
I have used a Windows 2000 professional 2000 and Visual Studio 6.00 with SP6. When i define a CMap class with integer key and CString object and i try to use the function of "SetAt" but it fail with assertion in the MFCD42.dll. The code is shown as follows.

defined in abc.h

CMap<int,int,CString, CString> m_packetPool;

defined in abc.cpp

m_packetPool.SetAt(1,"hello");

Then fail in the line of afxtempl.h
m_pFreeList=m_pFreeList->Next;

Could anybody help me? It is extremely urgent.

Thank you very much.

Best regards,
Paul

Did you tried to create a new Temporary projects and put these lines what you showed us ?
I tried at my place and works.... ( I'm using Vs 2005 ).
It's looks fine..... The posted code looks fine ..... but maybe you made some other things...?

Regards,
gili