OEM JOB running an OS command script fails

Hi There. On OEM 13.5 I am trying to get a OS Command Job to execute a Linux script on a server. If I am on the server itself and run the script it works fine but from within the job I get the following error:-

line 4: set: -A: invalid option
set: usage: set [-abefhkmnptuvxBCHP] [-o option-name] [--] [arg ...]

I do not know why it works from the server but OEM gives an error from within the same script. Any assistance would be greatly appreciated.

And this is the code from within the script:-

set -A myarray $AR_PARM

incSummary=${myarray[8]}