[hmmmmm]

PTaH is a different extension. If you don't know what it is you probably don't have it.
By "add new forward" he meant that he added a new forward, a function for plugin developers to use. You don't have to do anything to get the forward working (as long as the extension is running).

The "Failed to find signature" error indicates that you're either missing the gamedata file, in which case you should add it, or the signature in the gamedata file isn't valid, in which case e54385991 should fix it.