HELP --> 2501 and Catalyst 1900 switch problem. Cannot get e0 on router to come up when connected to any ports on switch @@@@

I'm trying to connect my 1900 switch to my router 2501 via ethernet 0 port router. The interface will come up but not the line protocol. If I plug the router into a hub and the switch into the same hub everything works. If I plug the cable from the e0 port to the aui port on the back of the switch it works. I cannot use any ports 1-24. I'm using a standard cable. I've reset the switch to factory default gave it an IP address. Any help would be great. Any suggestions please post. TIA