Could not calculate the upgrade -- Error Message (While doing Manual Update)

[Jatin Davey]

Hi all

While doing the manual update of the ubuntu 9.10 on my laptop using the 
GUI i get this error message.
*"Could not calculate the upgrade".*

It basically reads something from the cache and it goes on for about 25 
mins then i get this error message.

Complete Message is as below:

*Could not calculate the upgrade

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

This is most likely a transient problem, please try again later.*


Please help me on resolving this issue.

Thanks
Jatin