Cisco IP Communicator (CIPC) has a built-in web server, which is used for information purposes only. This scenario is similar to one in which you web into a 7910/40/60 IP phone. CIPC uses the port 80, which is also used by any web server. So when you run CIPC, it closes the port for the web server and opens the port for its own use.
With CIPC version 1.1(2) and later, you can disable the internal web server for CIPC. Create a Windows registry value with the regedit utility to do this.
You can also perform this procedure to disable the internal web server:
Open the Windows regedit utility from the Command-line Interface (CLI) or through Start > Run.
In the regedit utility, choose HKEY_LOCAL_MACHINE\SOFTWARE\Cisco Systems, Inc.\Communicator.
From the Edit menu, choose New > DWORD value.
Rename the WebServerDisabled value, and set it to any non-zero value.
Note: This value does not appear by default.
In order to enable the web server again, delete this key or set the key to zero.
Note: There is no option that allows you to change the port number in any version. The CIPC internal web server is hard-coded and cannot be configured, only disabled, at this time.
If you use a CIPC version earlier than 1.1(2), you must upgrade to CIPC version 1.1(2). In this version, you can disable the internal CIPC web server. You can download CIPC version 1.1(2) from Software Download-Cisco IP Communicator.
This issue is also documented in the Cisco bug ID CSCee81483.