You did call Ham_DOD_RoundRespawnEnt, and not Ham_DOD_RoundRespawn, right?
The include file has it listed as Ham_DOD_RoundRespawn in the "Execute Params" but I suspect a typo.
I would assume it started the loop (and happily called RoundRespawn on the first 32 player ents) and then died when it hit a real ent.
Otherwise, I can't really help - sadly I have absolutely no time to do anything fun / investigative with AMX ... I can only write what I know how to do, as I cannot test anything.
(Coding at work ;-) )