Thanks for the file pointer. I went and ran the file and get the following error message when trying to connect.
Unable to connect to database: saved admin password is incorrect. 0: C:\Program Files\SWsoft\Plesk\admin\auto_prepend\auth.php3:56 psaerror(string "Unable to connect to database: saved admin password is incorrect.")
When I run the file plesksrvclient.exe it also tells me it cannot connect to MySQL database.
Any thoughts?