If you do an Export All from the swpc_tex_tpa.erf file and then put all those files, the tpc2tga.exe file and THIS FILE (
http://webpages.charter.net/ytl/convert.bat) into the same folder someplace (I use a new folder under KotOR called "working" since it won't interfere with the game, but Override would work if you really want to put them all there) and try running that batch file I just linked.
It should work. Did for me. Though be advised to wait till the window closes before you go messing around with the files further. It'll take a while on slower machines.. Even on my P4 2.53 with 1 gig of PC2700 DDR it wasn't exactly "quick". When you're shelling out over 3000 batch commands PLUS the time it actually takes each file to convert, it takes a little bit. ;)
Anyways.. once you've got them in TGA format, you can delete the old files (ones without any extentions) if you want. Since once you edit a TGA, you just save it and drop it into Override to reskin something so the originals aren't much use since there's no TPC editor anyways that I know of =)
Well.. hope it's helpful.
*edit* Well, glad you got it worked out. I'll leave this one linked just in case someone else wants to batch convert the things. If the instructions are followed, it should work for anyone. :)
*/edit*
-Kitty