Using CSocketFile, does anyone know why I would receive an ASSERT FAILURE here?

ASSERT(m_pSocket->m_hSocket != INVALID_SOCKET);

The above line is part of SOCKCORE.CPP in the constructor of CSocketFile.

My app uses CSocketFile file(this) in OnReceive() fine, but when another part of the program calls a function written the same way I receive this assert failure. Thanks.