archive command Permission Denied?

Please bear with me. I am fairly new to Linux.

I am working on archiving my WAL files. For now I am just mailing
myself a list of the directory contents using the following script.

*-rwxr-xr-x 1 postgres postgres 87 Oct 28 20:23
/var/lib/pgsql/mail-WAL-list.sh*

the contents are simply

*ls -lrt /var/lib/pgsql/data/pg_xlog/ | mail -s "WAL files are:"
myemail(at)mydomain(dot)com*

I also have this set up to run in the postgres users cron at 8 a.m.

I can run this when logged on as postgres and the cron runs fine as
well, but I keep seeing the following in my logs.

*LOG: archive command failed with exit code 126
DETAIL: The failed archive command was: /var/lib/pgsql/mail-WAL-list.sh
WARNING: transaction log file "0000000100000000000000F0" could not be
archived: too many failures
sh: /var/lib/pgsql/mail-WAL-list.sh: Permission denied*

I would appreciate any advice on what permission I need to set in order
for this command to run.

--
Thank you for your time,

Jason Long
CEO and Chief Software Engineer
BS Physics, MS Chemical Engineering
http://www.octgsoftware.com
HJBug Founder and President
http://www.hjbug.com