Hi Mukul,
As of NW Release 7.3, you will not be able to implement the above said functionality on SU01/ SU10 through eCATT scripts. You will need to use a BAPI on your scripts going ahead. Check SAP Note 1864062 for more information.
It could be that you were on an earlier release the last time you ran the script successfully. Check if this is the cause and let us know.
Regards,
Pranaam