TSWeb Works from Home but Not Away

when I am on my home LAN and WLAN i have no problem doing a remote
connect. however when i go to work or some other location and try to
log in i get different results.

1) I can get to my TSWeb page and enter the computer name - no problem
2) The activex control is installed and working fine
3) When trying to log in I get this...

"The specified remote computer could not be found.Verify that you have
typed the correct computer name or IP address, and then try connecting
again."

or - if i try the IP Address (interesting to note that

"The client could not connect to the remote computer. Remote connections
might not be enabled or the computer might be too busy to accept new
connections. It is also possible that network problems are preventing
your connection.Please try connecting again later. If the problem
continues to occ, contact your administrator."

Any thoughts?