Whenever I try to install the updater, the program keeps telling me that the folder that is selected for Dreamweaver MX 2004 does not contain it (Dreamweaver MX 2004).

I have tried browsing to the correct folder (which ends up being the same one that was chosen before) and I still get the error. Because of this, I cannot install the updater.

Has anyone else encountered this problem, and if so, how do I fix it?

Unistall dreamweaver and redo over

What version of DW are you running? The updater will only update the shipping version of DW MX 2004. If you look at the properties of Dreamweaver.exe, what version does it have?