Can not save system alias SAP_R3_Procurement

I'm trying to map the alias "SAP_R3_Procurement" to a system that I earlier created. When I try to map the alias to that system, the portal will not let me save it. The portal does not give me an error to tell me what's wrong. The portal just erases SAP_R3_Procurement when I close the window.

This alias "SAP_R3_Procurement" is one used by the iViews in the business package. Could the problem be that the alias is already attached to some other system? How can I determine if an alias is mapped to a different system already? Or what might my problem be?

Thanks in advance!

Kevin