I have a lamp server running on ubuntu server edition, and I want to uninstall lamp.
sudo tasksel remove lamp-server returns tasksel: aptitude failed (100).
sudo tasksel --section server, then unselecting lamp-server also returns tasksel: aptitude failed (100).
sudo apt-get update, then either of the previous commands does the same thing.
Try sudo apt-get remove lamp-server^ --simulate
If that looks like what you want, remove the --simulate flag and actually do the uninstall.
A variation of that, targeting relevant packages manually, would be along the lines of :
sudo apt-get --simulate remove mysql-server apache2 php5 libapache2-mod-php5 openssh-server openssl
If there are other packages that depend on things like mysql that you want to keep, that might be a better way to go. Again, remove --simulate to actually run the command. (With apt-get, -s is equivalent to --simulate, and you would probably use it instead in day-to-day work.)
For the tasksel and aptitude problem in particular, you might try sudo apt-get autoclean and sudo apt-get clean to see if that clears the error.
