Well, first of all, it SHOULD (but, as we have seen, it doesn't) work with any P files. P files doesn't necesarily have .p extension (which is another error in my program). They can be found at chars.lgp, battle.lgp and magic.lgp (maybe somewhere more, don't know). The files at battle.lgp have no extension at all, but you can list them just typing *.* on the "Name" field and pressing enter. You can try for example "ehap" (Dyne's head). Take care that, even though most files in batte.lgp are p files, some are textures or skeleton files. If you try openning one of those, you will provabily get an out-of-index error.
PD.: I know I said that i ws going to release a new version soon and I'm kidna late, but I've been busy with the exams. I'll provabily release it before the end of this week-end though.