Error during restore

Hi,

I followed instructions for an uncompressed backup and restore here:
http://www.movabletype.org/documentation/administrator/maintenance/backup-and-restore.html

It threw an error and didn't complete the process. It looks like the cause is a custom field I assigned to users, for a postal code (basename: postalcode). I have another called Location that wasn't mentioned in the error.

The message in the Activity Log is:

Cannot find column 'field.postalcode' for class 'MT::Author' at lib/MT/BackupRestore/BackupFileHandler.pm line 130 at /usr/lib/perl5/XML/LibXML/SAX.pm line 63

Has anyone else had an issue with custom fields tripping up the restore process? Or have any tips? I'd rather not delete it from my original installation (I'm backing up to a second installation) because of the data we could lose.

Thanks!

Erika