The line "set -A USERMODS_OPTIONS" initializes USERMODS_OPTIONS as an array. I suspect commenting this line out would prevent the other lines from working if they were ever used in the future. As "set -A" is a ksh specific command, I wonder if /bin/ksh is not the correct path to the korn shell executable.
[user@hostname ~]$ /bin/ksh --version
version sh (AT&T Research) 93u+ 2012-08-01
[user@hostname ~]$
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Greg Wootton | Principal Systems Technical Support Engineer