Thanks for the wav file. I tested your wav file with different versions of mIRC, including v7.63, under Windows XP, 7, and 10 64bit, and was unable to reproduce a crash here. I played the wav file many times repeatedly in each case.
In the past, similar issues have been reported where a user had a corrupted codec installed that lead to a crash when it was used. Newer versions of mIRC use newer APIs, such as DirectSound, to play wav files.
Have you installed codecs in the past, such as VLC? You may need to uninstall and reinstall them to see if that helps.
You might also want to run dxdiag to see if it reports any issues.