Looking at the website you link to there does appear to be a lot of problems with this unit and certain CDs therefore that would appear to be the problem. Solution would be to use only the particular CDRs that Philips recommend - hopefully. Should be a compatability list in the manual or on their website.
To answer the question about audio and data CDRs I personally have seen no difference, audio CDRs are meant to give better sound quality or so I have been told but I can't tell the difference and because of that and because they are dearer I have never used them.
Have you tried a lens cleaner just in case?