Hi Seed,
I agree with the above advice: Event ID 6 messages can safely be ignored.
Here is an official article on the subject: "Could not scan [#] files inside [path][filename] due to extraction errors encountered by the Decomposer Engines" during a scan (http://www.symantec.com/docs/TECH99755)
I recommend having a look at the logging configuration passed down to clients from the SEPM. It's possible to set SEP clients so that they do not forward this (and other additional) high-volume, low-importance messages to the SEPM. That will keep the SEPM's reports from being full of these and will help keep the SEPM database size down.
Hope this helps!
Thanks and best regards,
Mick