The exact message is:
Vidalia was unable to start Tor. Check your settings to ensure the correct name and location of your Tor executable is specified.
Tor exists but vidalia couldn't see or read it. I click "Browse" & it says:
Unable to save bookmarks in /home/me/.kde/share/apps/kfileplaces/bookmarks.xml.
Reported error was:
Unable to open temporary file.. This error message will only be shown once. The cause of the error needs to be fixed as quickly as possible, which is most likely a full hard drive.
I added rwx permissions but problem doesn't resolve. I tried to run it as su, but there is problem with fontconfig & vidalia couldn't connect to x-server.
Of course I can use tor with tor-browser.
I use Kubuntu 12.10, vidalia 0.2.2. (I have seen this problem recently in Ubuntu 12.04 as well).