error (updated)

I got a bunch of errors like following in my Smarlist log file:

../.bin/subscribe: line 1: ./cat: Permission denied
../.bin/subscribe: line 112: ./cat: Permission denied
../.bin/subscribe: line 123: ./cat: Permission denied
../.bin/subscribe: line 140: ./cat: Permission denied
../.bin/subscribe: line 142: ./cat: Permission denied
../.bin/arch_retrieve: line 1: ./cat: Permission denied
../.bin/arch_retrieve: line 312: ./cat: Permission denied
../.bin/procbounce: line 142: ./cat: Permission denied

while the list still works on distributing group mails and take
sub/unsub requests.

I checked all possible file permissions and folder/file ownership
-- everything seem fine: /bin/cat - 755; ~slist/.bin/subscribe - 755;
the target files to read have 664 and user:group=slist:slist

One odd thing is every successfully posted mail is saved a copy into a
file called "cat" in the list directory, besides a regular copy saved
to archive/latest/.

Any suggestion where to look further?

Zhiliang