Can't load data source

I use RDM from work and "backup" and sometimes use from home.
I basically copy the MDB and config files from work and restore them at home. It's always worked until I reloaded a new PC, installed RDM, and copied the MDB and config files. Now I get the following error:
The current datasource is unavailable.
The provider could not determine the Object value. For example, the row was just created, the default for the Object column was not available, and the consumer had not yet set a new Object value.

If I create a new datasource (7.1.0.0 Enterprise and Access DB), then everything works. Everything still works when used from work. I left the master key blank when installing both locations.

Thanks!