Acrobat 6 instal -> finder crashing

[Lyra]

I just tried to install the Acrobat 6 upgrade on my dp G4, running 10.2.6. Not only couldn't I install it fully - it crashed every time I tried to enter the serial number - but now my finder's wigged out. Every time I try to access the 'Apple' menu in the top menu bar, the finder crashes. I can't open the system preferences, either, so I can't log out and log in as another user. I've repaired permissions, done a hard reboot (can't do anything else, as I can't access the 'Restart' command), neither of which made a difference. All the other elements of the menu bar seem to be OK.

Help?! What else can I try before I have to do a reinstall?

Later ... panic over, I think. I hadn't dumped preferences when I squealed for help. Now I have, and things seem to be back to normal. While I'm here, though, anyone else had problems with Acrobat 6? If you have, have you solved them?