It is worth a try. DO NOT reload the four variables files, just the rest of the cgi directory. Be sure you use the one with the correct perl path and upload in ascii mode. It should not be necessary to upload anything from the Members or nonCGI directory, but you may want to check to see that all of the gif and jpg files are present.
[To be safe, make copies of UltBB.setup, forums.cgi, mods.file, and Styles.file from your cgi directory before you start. Download in ascii mode to a separate directory or make copies in a separate directory on the server.]