Try to navigate to that share directly using Windows Explorer. I wonder if Windows has just forgotten the credentials used.
Also, in the latest release I added a backup/restore feature (from Amazon S3), that could be used as an alternative....?
The workflow would be:
1. User 1 has the current config, and backs it up to S3
2. User 2 restores S3 Configuration
3. User 2 updates configuration (add/remove/edits any entry) and backs it up to S3 (and lets everyone else know to get the newest rev)
4. User 1 restores S3 Configuraiton