When installing Exclaimer the application runs through a wizard to complete where you select the options such as spam filtering, antivirus etc and it fails with a scripting error:

To resolve this issue start a DOS prompt, switched to the c:\program files\exclaimer directory and then issue the following command twice.  It must be run twice, the first time unregisters the serivce and the second registers it again:

exserv.exe /service