If you try to run /scripts/pkgacct through shell and your load is not nominal, the script will stall. To bypass this and get it running you can use:
/usr/local/cpanel/bin/cpuwatch xx.x
So, if I want to backup an account with username "ayksolutions" to the directory /backup/cpbackup/daily and do this if the load is 30 or below, I would run the following command from prompt as root:
/usr/local/cpanel/bin/cpuwatch 30.0 /scripts/pkgacct ayksolutions /backup/cpbackup/daily