Just so you know I did a little digging with the extractor and it seems that some of the later texture pak files might be using a different encryption as unable to unpak them.
I think it automatically reassembles them into one archive, in effect (though I may be mistaken), so if you unpack the first of a series of files it'll do the rest of them at the same time.
Packages with numbers at the end of their names are multi-part packages; eg. Textures_2.pak is part 2 of Textures.pak. They cannot be extracted separately and are automatically extracted when you unpack the first part (Textures.pak)
That is what I thought but I extracted the first texture pak and it didn't seem to have much so went onto the next and it extracted more textures so it appears it doesn't.
