I have a Philips DVD R80 that has identical problems to the ones you describe: disc error for +r discs irrespective of the brand used, screen freezing when I start to record etc. Sometimes I get lucky and do manage to record something. Last week I managed after several attempts to recorded my holiday video onto a +r Verbatim DVD, but I can only occasionally play it back on the Philips machine.
I can however play it on my Father in laws SONY RDR GXD 500 machine. His machine can record perfectly on any format and can even play back! He has inherited all the DVD brands that have tried on Philips and failed
I think there can be no excuses from Philips, their technology is clearly inferior to their competitors. We shouldn't have to search for disc brands that we hope might work.
My machine is just over a year old but the problems occurred from day 1. I've tried firmware upgrades suggested by Philips and, of course, this made no difference. Unfortunately I didn't pursue the problems within the warrenty period as I was very busy with other things.
I'm now considering if I should invest the time and energy into trying to get philips to fix the problem. The alternative is just to buy a SONY machine and chuck the Philips machine in the bin where it belongs.
If I do get round to writing to Philips then I will quote this thread.