I looked up the details for that event id and the source you've specified appears to be incorrect: it should be NTFS
See the following for details:
http://social.technet.microsoft.com/Forums/windows/en-US/c9bbd077-9b27-4a3c-815a-f5a87f2a914e/error-logged-event-id-55-ntfs
So...
Event id equals 55
Event Source equals NTFS
It souned like you were onto something here. But.... the field for Event Source is a drop-down list, and NTFS, or even File System, is not one of the choices. And sure enough, if I open Event Viewer and look at one of the 55s, source is listed
as NTFS.
This is my list of choices:
Under Management Group it has Name and ID. I don't think that would help. It appears that I'm at a deadend. I'll Google more.