I think you are missing the 'fi' right before your last done:

if [ ${#syslog_array2[*]} > 0 ]; then
while [ ${i} -lt ${#syslog_array2[*]} ]
do
x=${syslog_array2[i]}
dbmatch='no'


if [ ${#pmon_array[*]} = 0 ]; then
ps -ef | grep nco_p_syslog | grep $x | awk '{print $2}' | xargs kill
else
k=0
while [ ${k} -lt ${#pmon_array[*]} ]
do
if [ ${syslog_array2[i]} == ${pmon_array[k]} ]; then
dbmatch='yes'
fi
k=`expr ${k} + 1`
done

if [ $dbmatch = 'no' ]; then
sleep 60
ps -ef | grep ora_pmon | grep -v grep | awk '{print $NF}' |\
awk -F_ '{print $NF}' > $OMNIHOME/bin/pmonfile.dat
set -A pmon_array
dbfile_name='pmonfile.dat'
l=0
host=`hostname`
while read dbname
do
pmon_array[l]=${dbname}
l=`expr ${l} + 1`
done < $OMNIHOME/bin/${dbfile_name}

k=0

while [ ${k} -lt ${#pmon_array[*]} ]
do
if [ ${syslog_array2[i]} == ${pmon_array[k]} ]; then
dbmatch='yes'
fi
k=`expr ${k} + 1`
done

if [ $dbmatch = 'no' ]; then
ps -ef | grep nco_p_syslog | grep $x | awk '{print $2}' | xargs kill
fi
fi

i=`expr ${i} + 1`
fi
done
fi