Does your file have data damage and if so why?

Data damage can be caused by many things in a QuickBooks file, much like any other software.  The best offense is a good defense.
Verify and if necessary Rebuild your data.  The links given sometimes move so if the link is broken just search the main (home) page for "verify"
http://support.quickbooks.intuit.com/support/Articles/SLN40678

Another good tool:
http://support.quickbooks.intuit.com/support/networking/nettool.aspx

Also make sure that you have the option checked to verify your data with each backup.  It's worth the extra time it may take.

Backing up and verifying data are extremely important and could save you hours (if not days or more) of time in the future.