Ran into this on a new MOSS 2007 installation (on Windows Server 2008), not sure why exactly, as it was a simple, standard install done a dozen or more times but I digress…
If you get this…
Failed to resolve the site ID for ‘Office Server Web Services’
It can be resolved with this…
stsadm -o provisionservice -action start -servicetype “Microsoft.Office.Excel.Server.ExcelServerSharedWebService, Microsoft.Office.Excel.Server, Version=12.0.0.0, Culture=neutral, PublicKeyToken=71e9bce111e9429c”