Changing the extension from mp4 to alac did cause WL to open the file but the playback was just noise; the loud, screeching kind of noise.
This file is new, I purchased and downloaded today.
I checked the file with MediaInfo and it is ‘normal’ w.r.t. sampling rate 44.1; bitrate 254; format AAC; format profile LC
Opening the mp4/AAC file isn’t mission critical here. Like said above, this is probably due to ‘operator error’ and nothing to do w/WaveLab. If QuickTime plays it w/o problems, same with WinAmp, I thought this would be a no-brainer in WL.