thefoxtrot please do the following:

Firstly take a look at this wiki page:
http://wiki.maemo.org/Free_up_rootfs_space

Do what they say there and learn about what you did wrong.

You should always check the space an app is taking after installing. Do that by in xterm do this and check how much you had before and after installing.
To remove packages manually:
Of course replace <package name> with an actual package name like apt-get remove dosbox