xwiki-enterprise-tomcat7-pgsql uninstall/reinstall bug in Ubuntu 12.04

Hi,

I cannot remove this package from my system. I wanted to actually install xwiki with mysql(xwiki-enterprise-tomcat7-mysql). It broke while creating database (mysql-5.5.29). Then I tried it with postgresql. I could not set it up with the user for xwiki. I tried to remove it and it crashed looking for tomcat 6. This is supposed to look for tomcat 7 if I am right. I cannot install tomcat 6 when tomcat 7 is already installed. My Synaptic Package Manager cannot remove/purge this application.

Preconfiguring packages ...
Selecting previously unselected package xwiki-enterprise-tomcat7-pgsql.
(Reading database ... 501135 files and directories currently installed.)
Preparing to replace xwiki-enterprise-tomcat7-pgsql 4.4.1 (using .../xwiki-enterprise-tomcat7-pgsql_4.4.1_all.deb) ...
Unpacking replacement xwiki-enterprise-tomcat7-pgsql ...

• tomcat6 is not installed
  dpkg: warning: subprocess old post-removal script returned error exit status 1
  dpkg - trying script from the new package instead ...
• tomcat6 is not installed
  dpkg: error processing /var/cache/apt/archives/xwiki-enterprise-tomcat7-pgsql_4.4.1_all.deb (--unpack):
  subprocess new post-removal script returned error exit status 1
• tomcat6 is not installed
  dpkg: error while cleaning up:
  subprocess new post-removal script returned error exit status 1

sudo apt-get install -f
Reading package lists... Done
Building dependency tree
Reading state information... Done
0 upgraded, 0 newly installed, 0 to remove and 0 not upgraded.
18 not fully installed or removed.
Need to get 0 B/1,340 B of archives.
After this operation, 0 B of additional disk space will be used.
(Reading database ... 501136 files and directories currently installed.)
Preparing to replace xwiki-enterprise-tomcat7-pgsql 4.4.1 (using .../xwiki-enterprise-tomcat7-pgsql_4.4.1_all.deb) ...
Unpacking replacement xwiki-enterprise-tomcat7-pgsql ...

• tomcat6 is not installed
  dpkg: warning: subprocess old post-removal script returned error exit status 1
  dpkg - trying script from the new package instead ...
• tomcat6 is not installed
  dpkg: error processing /var/cache/apt/archives/xwiki-enterprise-tomcat7-pgsql_4.4.1_all.deb (--unpack):
  subprocess new post-removal script returned error exit status 1
• tomcat6 is not installed
  dpkg: error while cleaning up:
  subprocess new post-removal script returned error exit status 1
  Errors were encountered while processing:
  /var/cache/apt/archives/xwiki-enterprise-tomcat7-pgsql_4.4.1_all.deb
  E: Sub-process /usr/bin/dpkg returned an error code (1)

Please address and advise ASAP.

Thanks and regards,
Sumanth