How to work "Remote Desktop Mobile"

How to work "Remote Desktop Mobile"   Hello, I have a T-Mobile MDA with a Windows Mobile 6.  I'd like to be able to know how to use the Remote Desktop Mobile yet every time I input all the information (such as Computet, user name and password) is get a "Connection Status" error message that says:........ Hello, I have a T-Mobile MDA with a Windows Mobile 6.  I'd like to be able to know how to use the Remote Desktop Mobile yet every time I input all the information (such as Computet, user name and password) is get a "Connection Status" error message that says: "CANNOT CONNECT. LIKELY REASONS ARE: 1. SPECIFIED COMPUTER NAME OR IP DOES NOT EXIST. 2. A NETWORK ERROR OCCURRED WHILE ESTABLISHING THE CONNECTION.  I have never been able to get past this message.  Can enybody help and say what I am doing wrong?  Thanks for your help.