Oracle RMAN Problems

I am having an ORA-19575 error when I am doing an Oracle RMAN backup this error is supposed to mean there is a problem with a file like it is corrupt but I have no errors in my alert file that shows such problems happening. I am running 8.1.7.4 on HP-UX 11 32bit. I was hoping to see if anyone else has this problem and how it could be fixed.