Free ESXi 4.1 u3 ghettoVCB.sh: line 836: syntax error: Bad substitution

I can't get ghettoVCB.sh to run on free ESXi v4.1.

Have copied the .sh and .conf files to /ghettoVCB-master .  When I enter ./ghettoVCB.sh I get:

ghettoVCB.sh: line 836: syntax error: Bad substitution

If I try /bin/ash ghettoVCB.sh I get exactly the same.

The execute bit is set:

/ghettoVCB-master # ls -l

-rw-------    1 root     root               1140 Nov  6 15:37 README.md

-rwx--x--x    1 root     root              17555 Nov  6 15:37 ghettoVCB-restore.sh

-rw-------    1 root     root                747 Nov  6 15:43 ghettoVCB.conf

-rwx--x--x    1 root     root              64593 Nov  6 16:23 ghettoVCB.sh

-rw-r--r--    1 root     root                 11 Nov  6 15:39 vms_to_backup

I can't see a ghettoVCB logfile in /tmp .

How can I troubleshoot this please?