Arunkumar,
I am not familiar enough with use of this extension to help much. But have you tried
1) single quotes?
2) modifying opcmsg.sh, ie
add: var=$(echo $var | sed 's/ /_/g')
# ./opcmsg.sh "My Application"
Total Variables: 1
My_Application
I don't know the context this script is used and maybe I misinterpreted the problem.