Upgrading from 2.4 to 2.6: LVM failed

[Filippos]

> Further, I think I have successfully upgraded to Core 2, that is, I
> have installed apt and I edited the sources.list and did
> 
>  apt-get update
>  apt-get dist-upgrade
> 

As a side note you forgot to do:

apt-get upgrade

which is the most time consuming one and upgrades all the packages
installed to newer versions that are not directly related to the
distribution.