Access/Excel import problems

We have recently began upgrading our 2000 terminal servers to 2003. For the
most partt, the transition has been ok, but have run into a problem that has
me stumped. We Publish applications, not desktops, for our users. One of the
primary functions some business reps do is take excel documents and import
them into access. To do this, they open excel on the 2000 (sp4) terminal
server (office xp sp1) create the spreadsheet, save it, then open access and
import the spreadsheet (with the spreadsheet open. On the 2003 server, (using
office xp sp1 or sp3) they try to do the samething, but get an error "the
wizard is unable to access information in the file (file location). Please
check that the file exists and is in the correct format. Closing the excel
file and doing the import works. Launching access from a desktop instead of
as a startup application also works.
I would appreciate anyone's suggestions on how to fix this error, or why
this happens with 2003, but not 2000.

Thanks