Those two are both definitley listed as m/c hybrid on SC-CD.NET so it is likely there is an issue with the player recognizing these discs correctly. I don't have either of those, so I can't tell you much more about the discs, but I used to have a Sony SCD-222ES which I believe was out around the same times as that one, possibly even the ES version of the same player. If you do have a button on the remote to switch between tracks, does it cycle to each (CD -> stereo -> m/c)? There should also be a setup menu that allows you to choose the default track type. Sounds like you may have it setup correctly already, since other discs work, but I'd still check those things to see if they make any difference.