How do I get more details on a full text catalog error?
According to a post in the MSDN forums, SQL Server 2005 (and probably earlier) contained a flaw that results in the error.  This was reported by "A Fellows" in his problem resolution back in 2010.

https://social.msdn.microsoft.com/Forums/sqlserver/en-US/9626c8f8-9171-4625-a9c0-ef72628066b9/fulltext-error-indexing-rows-with-jpgs

In part he says: "Well microsoft looked into it and with SQL2008 it works properly, with SQL2005 it doesn't ... (but) ... SQL2008 full text has been rewritten and works as it should." 

If you are still on SQL Server 2005 and still stuck with the problem, then he also offers a workaround of sorts for SQL Server 2005.