Access violation - memory corruption?

Hi Experts,

First off, I cannot post our code here, I have to keep this general.  Sorry in advance.

I have a call to a function where the first argument passed is an LPCSTR.  The actual parameter that the function takes is "const _variant_t & Source" (it's for a database query with ADO).

During the conversion of this string to the variant, there's an access violation on the AddRef here, from comutil.h:

inline _variant_t::_variant_t(IDispatch* pSrc, bool fAddRef) throw()
{
    V_VT(this) = VT_DISPATCH;
    V_DISPATCH(this) = pSrc;

    // Need the AddRef() as VariantClear() calls Release(), unless fAddRef
    // false indicates we're taking ownership
    //
    if (fAddRef) {
        if (V_DISPATCH(this) != NULL) {
            V_DISPATCH(this)->AddRef();  // KABOOM here...
        }
    }
}

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Note that this code is called frequently before some specific functions actually get through here without a hitch.  It's after a specific previous function that I found with a binary search that when commented out, the issue goes away.

My question is, would you agree that this is likely a heap error?  I tried to detect it with windbg with no luck.  I looked at the code in the function that when commented out, the problem goes away, but I don't see the problem yet.  Is it highly likely that this is where the problem is?

And my most important question of all-->  If we skate around this issue and change the code in ways where we don't really fix it, but the error remains hidden, if it doesn't happen on my machine any more in debug or release mode, and the input to the function remains constant on customer machines, is it possible that other factors can expose this problem differenly on other machines?  (This is the "solution" that is being pushed on me and I'm thinking it's a very very bad idea)...

What do you think?

Thanks,
Mike