Unlucky. The old exception error is bad enough, but in a report it tends to be at its worst. Just have a look here Unhandled Exception Error C0000005 - how to fix it!
in case any of this helps - although they were mostly not about report level problems. You might like to try putting the report in structure mode before it is refreshed.
Nick Daniels 
(BOB member since 2002-08-15)