Does the DB name have any escape characters in it like - "Sample's" ? If yes, then the issue is known and the fix will be available in the next release.
Running 4.30, I was busy working with my various databases, and when I clicked on one of them, I got a message box with the title "Error retrieving data from the server: INTERNAL SERVER ERROR" and the body "String indices must be integers".
I tried closing/reopening the browser client, but not it did not change the inability to open one of my databases. I then did a "Shut down server" from the Windows systray, and reopened the browser client, and then was able to open the database in question.
If you need any logs, please let me know where to find them on Windows 7, and I can open a RM.