It seems that you are having some issues while trying to connect to your Slingbox Classic.
If you get this specific error message it is because you are trying to connect to your Slingbox Classic using any of the SlingPlayer latest versions. The issue is that if this is your case, you will not be able to get this connection. The following link will provide you with all the information about the supported SlingPlayer software according to your Slingbox model:
If this is not your case, I recommend you to be as specific as possible about the issue you are having. This way, other forum users will be able to help you with accurate information
Hope this helps!