Upon installing a Call Center Edition adapter, some users may see the following error in red where the Softphone should be:

Error: Unable to start the Softphone XML subsystem. Please contact your Salesforce.com administrator to rectify this issue.

This error means that the XML subsystem, MSXML6, has not been installed or properly registered. 

The problem here is usually one of the following:

The person who installed the adapter did not have the proper privileges to register DLLs.

In this case, there are two possible workarounds.  The first is to follow this process (when logged in as a Windows administrator or at least a user who can register DLLs):

1. Navigate your Windows Explorer to c:\windows\system32.
2. Double click on msxml6.dll.  It'll give you a window saying it doesn't know what to do with it.  Select "select program from list."
3. In the ensuing window, press Browse.  There, type "c:\windows\system32\regsvr32".

The second workaround is to simply uninstall the adapter and reinstall it when logged in as an administrator.

If the above methods do not solve the problem, then the author of the adapter may have a bug in their installer.

If this is the case, the customer should contact the author of the adapter and ask whether it is installing MSXML6.