WMI question

Hi guys,
   I am working on a WMI application that keeps crashing when I perform
certain queries. The program will eventually perform 349 different types of
WMI queries, but at this point it only successfully works for a limited
number of those. I have written the project framework and have all the
needed functionality already included, the code compiles cleanly and works
perfectly when I query for certain things such as all running processes, but
it crashes with an access violation when I run various other queries. One
query that crashes the program is the Win32_AccountSID. I am running this
code from an administrator account on an XP Pro Sp2 machine and I am using
MSVC6.0 Professional compiler.

  I can send my code to anyone that might be able to help with this problem
if they need it. I break into the debugger when the program crashes and this
is the code that seems to be causing the problem:

size_t __cdecl wcslen (
        const wchar_t * wcs
        )
{
        const wchar_t *eos = wcs;
        while( *eos++ ) ;    //here is where the instruction pointer is
pointing when the debugger loads
        return( (size_t)(eos - wcs - 1) );
}


I'm wondering if the information I am querying for (i.e. Win32_AccountSID)
in this case, is returning information that is not what the wcslen( ) is
expecting... Why else would the 'eos' pointer incrementation cause the
access violation?  Any ideas?