Quartus v7.2 - UBUNTU v8.04, Hardy

You could try copying a "libX11.so.6.2.0" from a supported distribution into your Quartus distribution and then making the appropriate links, like so:

-rw-r--r-- 1 root root 777376 2008-02-12 14:49 /opt/altera/7.2/quartus/linux/libX11.so.6.2.0
lrwxrwxrwx 1 root root     15 2008-02-12 14:50 /opt/altera/7.2/quartus/linux/libX11.so.6.2 -> libX11.so.6.2.0
lrwxrwxrwx 1 root root     13 2008-02-12 14:50 /opt/altera/7.2/quartus/linux/libX11.so.6 -> libX11.so.6.2

Also, note any strange messages (dmesg or in /var/log/messages) to see if that gives you any clues.

There is no magic recipe that will always work and Altera is better than most vendors with respect to Linux support. In my mind, most of the issues that do exist are due to the choice of Mainwin for the GUI, but I don't think that's going to change anytime soon.

Good luck!