This is because tor is starting as a "system service".
$ ls -l /etc/rc2.d/S20tor
lrwxrwxrwx 1 root root 13 May 23 2009 /etc/rc2.d/S20tor -> ../init.d/tor
When you run Vidalia, tor needs to run tor under your user account. Vidalia tries to start tor but can't, because it's already running. So you need to stop tor before running Vidalia:
$ sudo /etc/init.d/tor stop
If you don't have the need to run tor at system start up (because you always use Vidalia for example), edit /etc/default/tor and set RUN_DAEMON to "no".
This is because tor is starting as a "system service".
$ ls -l /etc/rc2.d/S20tor
lrwxrwxrwx 1 root root 13 May 23 2009 /etc/rc2.d/S20tor -> ../init.d/tor
When you run Vidalia, tor needs to run tor under your user account. Vidalia tries to start tor but can't, because it's already running. So you need to stop tor before running Vidalia:
$ sudo /etc/init.d/tor stop
If you don't have the need to run tor at system start up (because you always use Vidalia for example), edit /etc/default/tor and set RUN_DAEMON to "no".