Hi Rao,
Please follow link Step-by-step Sapscript Barcode Printing - ABAP Development - SCN Wiki
Also please share results after following below:
1.Go to SE73 --> System Bar Codes ---> Display --> Select BAR_CODE(Demo) ---> Test Bar code ---> Execute (Print preview) -->Print .
If Print comes out then test for customized Bar code at your end.
Regards,
Gaurav