it is 'almost' impossible to move a program like that anyway...just copying files seldom works, as lots of things need to be written to the registry, etc..so you are at least on the right track.

You didn't say if you are trying to do the free version or not, but I agree that you need to close EVERYTHING that might disapprove of the installation.
One trick I have used is to read the 'exact' error message about 'uninstaller' or whatever, and paste some set of words from it into Google "groups" search....on the theory that someone has had the same problem and had it answered.

(It is also possible that, if you are now in XP as opposed to Win98 or something, that some procedure is different with the new OS...but as professional as Eudora is, it oughta work.)