Port forwarding will "forward" an incoming connection at a port on the SME to a port on a local PC. By "...external port 5641, local IP address, 5631, and 5642, local IP address, 5632 representing the 2 pcanywhere ports needed.", it sounds like you have ports 5641 and 5642 on the SME forwarded to ports 5631 and 5632 on a local PC respectively. This means that connecting to ports 5641and 5642 of your SME's public IP would have the same effect as connecting directly to the PC's IP (if the IP were accessible, like from the LAN) on ports 5631 and 5632. In most cases, you'll want to forward to the same port of the PC that the SME is receiving the connection on, i.e. 5641->5641 and 5642->5642.
When you connect to the forwarded ports, it should be exactly the same as connecting to the PC directly (since the SME is sending anything on those ports to the PC to be handled). If you mean directly dialing in by modem to the PC, then port forwarding has nothing to do with it. The login stuff sounds like PCanywhere, and possible setup issues with it (like Nathan said about the different types of security and such).