"please report this as a bug" message when attempting upgrade to dapper.

[tanifa]

i'm running this:
gksu "update-manager -d"

after clicking upgrade

i get this dialog:
"Can't install 'kubuntu-desktop'

It was impossible to install a required package. Please report this as a bug. "

and then i get:
"Could not calculate the upgrade

A unresolvable problem occured while calculating the upgrade. Please report this as a bug. "

So, where to report this as a bug? and how do i upgrade to dapper?