could not calculate the upgrade

[Tapas Mishra]

I was updating from 10.04 to 10.10 (was updating through update manager))
after some time I got following message

An unresolvable problem occurred while calculating the upgrade:
E:Unable to correct problems, you have held broken packages.

 This can be caused by:
 * Upgrading to a pre-release version of Ubuntu
 * Running the current pre-release version of Ubuntu
 * Unofficial software packages not provided by Ubuntu

If none of this applies, then please report this bug against the
'update-manager' package and include the files in
/var/log/dist-upgrade/ in the bug report.


What do I need to do now?