S_PROGNAM relates to you and SU53 is your result, but it is not needed as it is a SACF (see the tcode) object and running passively. It is not stopping you from anything.
What IS stopping you is that the program in which you are searching for the string does not directly contain that string in a static search. Hence string not found...
If you want to fix this issue you must add the string you are looking for to the code. Or at least a comment in the code. Then it will find it (also with the same authorizations).
So it is not there. It is now caching either.
Cheers,
Julius