re-converting ubuntu server edition

[C. Ahmet MERCAN]

Hi;

Previously, I did an dirty upgrade (via editing sourcelist file) from
6.06 server edition to 7.04, and than to 7.10. But while these upgrades,
somehow my server edition turned to hybrid system that does not contain
ubuntu-desktop package but with desktop kernel. update-manager gives an
error something like "i can not determine your ubuntu edition".

I tried to find/install an ubuntu-server package to fixing this problem.
  I tried to re-install linux-image-server package. Now i have an system
thats runs with a server kernel but the problem did not solved. Also
google did not help me.

Best regards.

Ahmet MERCAN