Problem in Redo log backup

Hi

I am trying to take "redo log backup" through db13 but it show following error and terminate.

BR0252E Function fopen() failed for '/oracle/SEP/saparch/aeatzgjn.cds' at location file_printout-4

BR0253E errno 2: No such file or directory

External program terminated with exit code 5

Regards

Vikram