Because those files are corrupted.
It will write in errorlog this:
SYSERR: Nov 9 16:21:27 :: Process: FDWATCH: peer null in event: ident 21
SYSERR: Nov 9 16:21:43 :: Process: FDWATCH: peer null in event: ident 21
SYSERR: Nov 9 16:21:44 :: Process: FDWATCH: peer null in event: ident 22
SYSERR: Nov 9 16:21:44 :: Process: FDWATCH: peer null in event: ident 23
SYSERR: Nov 9 16:22:01 :: Process: FDWATCH: peer null in event: ident 23
and your core will restart, restart, restart... making it unable to join and play.
Nobody can solve this problem, because nobody knows, why this error appears - it's just corrupted.
Lot of ppl have this error with these files. Don't use them. Better try other files.
I'm using those files and never had this error once.