"Invalid catalog file" message appears when trying to import a catalog with the To Existing Catalog check box set. The catalog imports without error when To Existing Catalog is not set.
Use Microsoft Access to open the catalog.mdb file in the source catalog.
Use the Compact & Repair tool in Microsoft Access.
Export the source catalog.
Try importing the new .CTLG file.
The above process worked for one user. It may be necessary to Compact & Repair the destination database in other cases.
Try importing a local copy of the .CTLG file into a local version of the catalog.
Try using a different workstation to perform the import.