I'm no programmer, but in doing a little research on a couple of errors, I found this explanation for the R6025 (follow the link for more information and the example code):
http://support.microsoft.com/kb/125749
CAUSE
"This error occurs when your application indirectly calls a pure virtual member function in a context where a call to the function is not valid. In most cases, the compiler detects this and reports the error when building the application. But depending on how your code is written, sometimes the problem is detected only at run-time.
The error occurs when you indirectly call a pure virtual function within the context of a call to the constructor or destructor of an abstract base class. This is illustrated in the sample code below, along with some more description."
Not much help to me, but I thought someone else might find it useful.
Vaughan