Backup and restore

I am trying to restore a course from a backup, but the restore fails with this error message:



Could not restore modules!
An error has occurred and the restore could not be completed!



Strangely, when I backup to a "new course", a new course is indeed created. However, none of the modules are created properly; there are icons, but no actual modules.

So I ask -- not really expecting any answers, of course -- why would an attempt to restore a course generate the error message reading, "Could not restore modules!"? My Apache error logs show nothing, of course. This error message is unnecessarily vague, in my opinion, and gives no idea of how to go about solving the problem. Could this be a permissions issue? A problem with database connectivity? Gremlins?

If anyone has a solution -- or just a hint as to where I could go to find a solution, or at least what's causing the problem -- I would really appreciate hearing it.

Currently using Moodle 1.4.2. For various reasons, we are unable to upgrade to 1.5 right now, so please don't suggest that as a solution.

(Sorry for the brusque tone; this is brand new behavior, and we are going live with several courses TODAY, and this issue is a showstopper for us, and I am quite frustrated.)

Cross-posted to "General Problems" forum because I didn't see that this forum existed originally.