Does the error report an error number?
[url="http://mails.datawatch.com/cgi-bin/ultimatebb.cgi?ubb=get_topic;f=1;t=000360"]This[/url] thread from some time back may (or may not) have some relevance.
The other odd thing that can occur relates to appending to existing sheets where formatting for things like currency and dates in the appended data is not applied in line with any originally exported formatting from an earlier export to the sheet but I cannot recall this being reported as producing a Jet error.
Which version of Monarch are you using?
[size="1"][ February 07, 2007, 12:51 PM: Message edited by: Todd Niemi ][/size]