Why might Server.ExpansionFactor be @Error?

Any idea why just one of our ~30 Domino 6.5 mail servers reports that Server.ExpansionFactor is @Error? Its load, hardware, and configuration are comparable (but not identical) to those of the other servers.

Subject: Checking loadmon.ncf now…

All the values in loadmon.ncf were 0 on the affected server, which seems unlikely to be a natural ocurrence, or a good one. I’ll report back once I’ve had a chance to let the server recreate a normal version.