I think what may have happened is that when SSMA upsized the db, you selected the option to have Access be upgraded as well and attached to the new SQL db, but because this was the BE, that doesn't work so well.
At this time I would delete the table attachments from the FE, then link to the SQL Server tables using the ODBC linked table features in Access.
Are you still at A2000? That's now 2002 - 2003 - 2007 - 2010 - 2013: 5 versions and 13 years behind the times. It may be time to cash in on your luck and consider an upgrade. Note that the Access Runtime is now free - has been for several versions, so only
developers need to spend money on the new version.
-Tom. Microsoft Access MVP