Can't extract all the textures

[Blightwolf]

There are 4 texture .pak files (textures.pak, textures_1.pak, textures_2.pak, and textures_3.pak) I'm able to extract Textures.pak but it won't extract the other 3 and when I try to I get an error "The specified file is part of a multi-part package..." but I don't have the textures I'm looking for. Is there something I need to do to make sure that all 4 paks are extracted?