Asked to Login Over and Over

Finally got to install trial version. Love the software but have a problem. Installed the software on a new server with Windows 2003 Enterprise Edition. The web client works fine if you are actually on the server. If you try to access the web client from any other computer on the network, you must login over and over. For example, if you login from a workstation other than the server, you browse to the main page and have to login twice. Then if you choose anything from the main dashboard page, say new request or inventory it takes you back to the login screen where you key in your login details agan. When you click login again, it takes you to where you wanted to go until you change sections again and the process of login repeats. Any thoughts on what I need to change? I installed 4103. Thanks!