Thank you for your post!
The issue you have is most likely with Read/Write Permissions for the file.
For Mac I would check permissions: Setting OS level permission via Terminal on OS X (Restart FMServer after following instructions)
For Windows I'd recommend uploading via client: Uploading database files to FileMaker Server
I hope this helps!
Also, I am going to move this thread from the FileMaker Community Feedback Space, which is specifically for input on the Community itself, to the Discussions Space where you should receive more views and potentially more advice!