Hi Pradeep,
As I see you have Oracle 11g running with 7.00 brtools patch
BR0051I BRBACKUP 7.00 (40)
Firstly update your brtools with 720 patch.
Post this if the error still persists following the instructions for dropping and re-creating the temp file again.
New datafile can be of 2 GB .
Hope this helps.
Regards,
Deepak Kori