After months of running fine I had an issue with the config page the other day where the header and menu column would show but not the centre content frame - the page is made up of 3 frames.
In the end I found that clicking the Compatability View button in IE8 solved the problem, but clicking it back off again didn't bring the problem back. This only worked temporarily and I had to keep messing with this option to get the content frame to display. Adding my server's IP address to the Local Intranet zone for IE and setting the IE option to automatically detect intranet traffic has given a permanent fix, though.
But you're using Ubuntu so probably don't use IE!
Shows that it could be a browser problem and not always TMS's fault.