To determine the port MSDE is using, run the SQL Server Network Utility on the machine hosting the MSDE instance. The SQL Server Network Utility can be found at \Program Files\Microsoft SQL Server\80\Tools\Binn\svrnetcn.exe.
On the general tab, select the TIMELESS_MSDE instance. Select TCP/IP and press the Properties button. Make a note of the default port. This is the port you will need.