Thank you for your post, and I apologize for the late reply.
Adding a new database file to the server would not cause the sharing to be inaccessible, so I think this is just coincidental.
Was there any update(s) to the OS recently?
Please look over Knowledge Base Article #5493 to cover all bases:
If you still cannot resolve the problem, and since this did work previously, I would start by uninstalling and reinstalling FileMaker Server. That is, find some time where you can perform maintenance on the server. Close the database files and move them into a folder on the Desktop. Stop FileMaker Server, uninstall FileMaker Server, and remove any files leftover from the uninstall. Reinstall FileMaker Server, redeploy, move the database files from the Desktop into the Databases folder, open the database files, and try accessing the files remotely again.
If you have already resolved this issue, please let me know what you did as this may be helpful to other customers who encounter the same problem.