Plesk not starting after Ubuntu upgrade

[solex16]

I am on VPS with Plesk 8.3 and upgraded from Ubuntu 6.06 to 7.1

All is working fine after the upgrade but Plesk fails to start..Virtuozzo is fine.

I ran
/etc/init.d/psa start

and got:
Starting xinetd service... done
Starting bind9 service... done
Starting mysql service... done
Starting qmail service... done
Starting courier-imap service... done
Starting postgresql service... not installed
Starting psa-spamassassin service... done
[Tue May 20 15:42:31 2008] [warn] The Alias directive in /etc/apache2/apache2.conf at line 129 will probably never match because it overlaps an earlier Alias.
[Tue May 20 15:42:41 2008] [warn] The Alias directive in /etc/apache2/apache2.conf at line 129 will probably never match because it overlaps an earlier Alias.
Starting Plesk... failed


What else can I do to find out why it's failing?..