source is a bashism. Ubunut uses dash as its /bin/sh. dash doesn't support source. If you want to use bash change the shebang at the top of your script to #!/bin/bash
If you want to make your scripts portable use . instead.
Code:
SCRIPT_HOME=/home/dhanushka/project/mChoise_Recharge/scripts/scriptfw
TAPE_DRV=/dev/st0
. $SCRIPT_HOME/conf/system.conf
. $SCRIPT_HOME/src/logging.bin
. $SCRIPT_HOME/src/tape_backup.bin