It seems that FlashChat hasnt been updated since 2009. Its currently at version 6.0.8.
The last install guide they provide for any type of software which is related to UBB.threads, is dated around 2007. That is for FlashChat version 4.7.9.
The version I believe you are attempting to install, is from 2004, for FlashChat 3.9. Although they are calling it, "UBB.threads integration" the documents within it, are calling it "ubbthreads," which is actually UBB.threads 6.2.x - 6.5.x, which i believe is before UBB.threads got the case and the "dot" in its name.
http://www.tufat.com/flashchat-2/
