Specified Cast is not Valid

Specified Cast is not Valid

When running a MOM-style import...

A client may receive an error like: 
 
"Import failed- Reason:  Specifed cast is not valid
Error in OnStart(): Import Failed."

At this time the only know resolution is to reboot the App server.  Stopping/restarting the IIS Admin and WWW service apparently have no effect.  Two different clients report that restarting the APP server is the only way to resolve the error.