If you can tell us what error you got when decompressing maybe we can help and try checking the arc.ini you are using is used in the include or " X " folder that the installer uses is the same arc file . Also try to replace the unarc.dll file which you can fined in " Glass Black Box " script post (or) " Black Box V2 " that file supports encryption , decryption and some unmatched compression methods i`m using the same unarc.dll file and it worked very good for me .