What OS are you using?

Maybe you need to code it this way::

Code:
# -- Etc...
typeset -i ReturnStatus=`
sqlplus -s /nolog << !EOF
-- etc --
!EOF`
echo "ReturnStatus=${ReturnStatus}"
# -- Try these:
if [ ReturnStatus -eq 0 ]; then      # or:
if [[ "$ReturnStatus" = "0" ]]; then
# -- Etc...
Also make sure CLONE_SETUP.clone_main returns a value!

PS: Notice I removed the redirection to the $LOG from the sqlplus statement