I had the same problem with RaidenFF ,
if you open the .def file you'll see this :
[Info]
name="name of the char"
displayname="name of the char"
versiondate=2007,03,05
mugenversion=06,14,2003
author="authorname"
pal.defaults=4,5,6,1,2,3,10,11,12,7,8,9
just make it look like this (simply adding a
[Info]
name="name of the char"
displayname="name of the char"
;versiondate=2007,03,05
;mugenversion=06,14,2003
;author="authorname"
pal.defaults=4,5,6,1,2,3,10,11,12,7,8,9 (verify the pal by defaults exists)
I don't know where was the problem but when I made this , RaidenFF worked !