what files did you download of bote? you need all of them which are located in the downloads section conveniently except the first one with the english translation. install them top down in the list and it should work. if not there is a handy "all-in-one" installer here: http://users.fulladsl.be/spb1497/BoE/Botf2_v051b.exe
the exe is a bit older than the latest one (which gets updated more frequently than the rest of the content, that's why it has a separate download of its own) so download that one again from this site's downloads section.
the size is roughly 45mb (don't worry, it'll be nearly double as much the next release
).