AV blocks file even though the file is in excluded list

WindowsXP 64 bit SP2, CIS 3.11.108364.552

I have a false positive file (a wav file detected as a malware). Even though I put the file into the excluded list, I can not access the file (I can’t play it).
If the file is put it in the my own safe files list from defense+, then the problem is solved. This can only be done from the virus alert dialog, not from the defense+/my own safe file/add, because from there is not accepted not being an executable file.