It seems that the current disk image available for Flip4Mac WMV Player 2.3.6.5 from Telestream, Microsoft or others will not mount 'because of an invalid checksum'. The wait is for a working updater.
You're right, interesting. I hadn't tried VT in an attempt to avoid the subsequent request to review the download, but it's the only one that works for me so far. The other sources still produce that error message when trying to mount the image.