Dunno.  The mutators were compiled in the beta 1.1 patch.  The only thing I can think of off the top of my head is the section header is wrong.  But since you said you were working on it for a while you probably already thought of the section header.

You can try:

[dFb_MutPack1anf.dFb_Spawn_Protection2nf]

Or 

[dFb_Spawn_Protection2nf.dFb_Spawn_Protection2nf]