I was running in to a problem configuring the Search Service on a MOSS install today. Trolling through the logs showed an error "The call to SearchServiceInstance.Provision <xxxxxxx> failed."
Stupidly, I'd forgotten to qualify the account names for the Search Service and Search Content Access with the local system's name, i.e. "MossSystemName\MossSearchSA". Yet another case of idiotic error handling in SharePoint helping me to shoot myself in the foot.
What's ironic is that just a couple months ago I had to keep reminding a client to add that system name to this field -- and here I am doing the same thing today. Duh.
(And of course Sahil posted on this too some time back.)