what exact patch have you installed?
upgrading from 8.3.01 - 9.1
you need to install platform patch for
8.4.01
9.1.00
REBOOT the server
than application patch for 9.1
REBOOT the server
UPGRADE DB from ssgconfig menu
and you should be good to go!
NOTE when going from 8.3.01 you can not go to 9.00
Thanks
Kemal