Jon,
It's not the foxuser.dbf (the resource file) that suffers index corruption. It your application tables themselves. Unfortunately these errors usually manifest themselves in the middle of a SQL-SELECT command or SEEK and it's pretty hard to catch them before hand. You could write a maintenence app that exercises all of the indexes, but it'll have to write its progress out to an external datastore that it can reread post C05 error to determine the candidate corruption.
Look at this list of Wiki articles
http://fox.wikis.com/wc.dll?Wiki~CategoryDataCorruption>I'm in the midst of tracking some c0000005's..I see everywhere that people say that FOXUSER.DBF index corruption is often the cause of some of these errors.
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>My question is, is there a way to tell whether or not a .DBF contains corruption *before* attempting to reindex/recreate it?