I downloaded the alt install CD for Ubuntu 11.04 so that I could run the media around my network to upgrade several machines vs. having each of them download the updates repeatedly. (This is the first time that have I tried this approach for the upgrade for Ubuntu.)

I ran into a weird error...

Could not calculate the upgrade

An unresolvable problem occurred while calculating the upgrade:
The package 'update-manager-kde' is marked for removal but it is in the removal blacklist.

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

After a bit of searching it appears that moving the KDE Manager should resolve the problem.

sudo apt-get remove update-manager-kde

I am running the upgrade on the machine that threw that error right now. At first glance it appears that the step abovet has resolved the problem.