I was getting the following error in my SharePoint. It was tracked by System Center Operations Manager 2007.
Event Type: ErrorEvent
Source: Office SharePoint ServerEvent
Category: User Profiles Event ID: 5553
Time: 11:00:02 AM
Description:failure trying to synch site bc0e54f5-b924-48b7-9196-0e383c80a078 for ContentDB ab1e590d-582c-4bdc-9ce5-47ec2607372a WebApp b3d80439-d3b8-4749-afc1-5a88e720ea9f. Exception message was Access is denied. (Exception from HRESULT: 0x80070005 (E_ACCESSDENIED)).
Some quick search on the web found me this cool tool
SharePoint Inspector. http://www.codeplex.com/spi.
this tool allowed me to decode the database id and web application in the event log error to web application and database instances.
From there a quick stsadm based on a fix here, it all worked out :)
Hope this helps you too