For troubleshooting why the Web App Server says the port is in use...
Windows XP and 2003 have the tools built-in to determine what process is using a specific TCP/IP port. If you are using some other version of windows, you will not be able to continue as below. But there are still a number of third-party tools available which can be downloaded instead. One such tool that has been used successfully by several people is fport.
From a command prompt, run netstat -o. This will output a list of ports, along with the PID (process ID) that has that port open. The output looks something like:
The sample output above indicates that the local port 80 is being used by process id 2636.
C:\Documents and Settings\Administrator>netstat -o
Proto Local Address Foreign Address State PID
TCP WEBAPPSERVER2:80 220.127.116.11:57434 TIME_WAIT 2636
TCP WEBAPPSERVER2:80 18.104.22.168:57589 TIME_WAIT 2636
TCP WEBAPPSERVER2:80 22.214.171.124:57600 TIME_WAIT 2636
TCP WEBAPPSERVER2:80 126.96.36.199:57608 TIME_WAIT 2636
TCP WEBAPPSERVER2:3389 188.8.131.52:6473 ESTABLISHED 964
TCP WEBAPPSERVER2:2325 192.168.0.13:netbios-ssn TIME_WAIT 0
C:\Documents and Settings\Administrator>
To determine what executable is running as a process ID, open Windows Task Manager and switch to the Processes tab. Now click on View->Select Columns... On the screen that opens, make sure "PID (Process Identifier)" is checked and then click OK. Now click on the PID heading to sort the entries by PID. The screen below shows that PID 2636 is alpha5.exe, indicating that it is the Web Application Server using port 80 in this case.