Metamod refuses to accept a plugin with dynamic polymorphism.

Hello. 
I am developing a mod for cs 1.6 via metamod. The problem is that if you use inheritor classes with dynamic polymorphism, the metamode refuses to load the library, marking it as "badf", without reporting an error, even with the debug mod enabled. What could be the reason? The metamod is compiled on the host from the source code. 

Thank you in advance.