Upgrade Plesk : everything work fine except Plesk

[karicom.com]

Hi my web site work fine webmail and D.B SSh ,but i can t use my controle panel .
I have plesk 8.1 and i upgrading to 8.2 and promotion ended successfully .after re-booting my server and whene i try to log in i have a page error .

is there a solution !!
and how can i restart my pelsk