Thank you for your post.
Do you have any startup scripts that write to the database? If so, this could display the error.
If you create a new database file with two accounts (Admin and Guest) and then open with server, is there any problem opening the file with Guest (Read Only) access?
Any additional information you can provide may help narrow the possible causes.
No startup scripts. The weird thing is it only happens when I have it up on the server -- if I'm running a local copy of the database from my Mac, the read-only accounts work.
So I did a "recover" (which said it didn't find any problems), toggled network sharing off and back on, and put the recovered version up and it worked while on the server.
I just can't figure out why the original version wouldn't work from the server.
But I guess it's resolved now...
If you possibly can do so, replace your recovered file with an undamaged backup copy.
While filemaker's recover tool is much improved, using a recovered file always runs the risk that the recover process changed your file in some unpredictable way.