Hello Chandan,
The command used there from BRBACKUP could be tested from sqlplus as well :
sqlplus "/ as sysoper"
alter database backup controlfile to '<path>/<filename>';
exit;
You can try to use different filesystems to create the copy of controlfile. It really looks lik the current file system path "/oracle/JMP/sapbackup" is having the problem. Please try a different location and check.
I guess, it's either a filesystem privilegies issue or the owner of Oracle or BR* executables is not correctly set Please check SAP notes #113747 and #583861.
Regards,
Arun.