Microsoft say this about Winsock error 10091 - WSASYSNOTREADY:

This error is returned by WSAStartup if the Windows Sockets implementation cannot function at this time because the underlying system it uses to provide network services is currently unavailable. Users should check: That the appropriate Windows Sockets DLL file is in the current path. That they are not trying to use more than one Windows Sockets implementation simultaneously. If there is more than one Winsock DLL on your system, be sure the first one in the path is appropriate for the network subsystem currently loaded. The Windows Sockets implementation documentation to be sure all necessary components are currently installed and configured correctly.

Full details of Winsock TCP error 10091 - WSASYSNOTREADY:

Berkeley description: No equivalent.

WinSock description: The WinSock implementation cannot function at this time, because the underlying system it uses to provide network services is currently unavailable.

User suggestions:

• Check that the WINSOCK.DLL file is in the current path
• Check that the WINSOCK.DLL file is from the same vendor as your underlying protocol stack. You cannot mix and match (WINSOCK DLLs must be supplied by the same vendor that provided your underlying protocol stack).
• You cannot use more than one WinSock implementation simultaneously. If you have more than one WINSOCK DLL on your system, be sure the first one in the path is appropriate for the network subsystem currently loaded.
• Check your WinSock implementation documentation to be sure all necessary components are currently installed and configured correctly.