Problems with M4V, MP4 files and TiVos

OK, let me start this out with me saying I'm sure I'm doing something wrong, just not sure what....

I've got a handful of videos, MP4 and M4V format (DVDs converted with Handbrake).

I want to play these on my TiVos (Roamio, Premiere).

Nothing too complex, as I've got a few other MP4s on them already...or so I thought....

For some unknown to me reason, none of them are showing up in TiVo Desktop Plus, therefore, can't get them to TiVos though guessing they wouldn't work anyhow since they don't show up on Desktop Plus.

Is there something I've missed in Desktop Plus that I did before and missed this time or maybe something in the conversion process?

I've gone thru the process a couple times, the videos play fine, so it's not corrupted, just not showing up.

Any ideas or suggestions?

Thanks!
Chris