Weirdness w/ Philips DVP-642 & burned DVDs

[cattrfly]

I've had the DVP-642 for a few months now, and haven't had a problem playing retail DVDs or avi's burned to CD, but I recently bought a DVD burner and now I'm running into trouble with playing avi's burned to DVD.
First DVD I burned was 12 episodes of a tv show - only 7 of them showed up in the player's menu, though they all show up and play fine when I put the DVD in my Mac.

I thought the problem might be caused by all the file names being the same thanks to the player's character limit ("ShowNameS1_EpisodeName" became "ShowNameS1" for all eps), so I altered the file names and burned another DVD.

Second DVD showed all eps in the player's menu normally at first, but when I tried to watch - first ep I chose played perfectly, skipped forward to next ep, played well until about 3/4 through then started to freeze and eventually dumped me back to the menu. Tried to replay problem ep and found fast-forward was now prohibited. Tried to skip forward to next ep and was dumped back to the menu again. The menu now showed all eps after the one I had successfully watched with a question mark icon in place of the MPEG-4 icon they had previously had, and took forever (2 min. or more) when I tried to scroll to one of them with the arrow buttons. I turned the player off (when it finally allowed me to) and gave up.

The next day when I tried to play the same DVD, the whole process sort of repeated itself - all eps appeared normal in menu at first, watched ep that had started to freeze before with no problems, skipped to next ep which started to freeze about 3/4 through, dumped back to menu, and so on.

It seems if I let the player "rest" overnight it will behave normally until I've watched about 1.75 episodes (originally 1hr. each minus commercials) and then get cranky. Is this something I should be calling Philips about, or could the problem be related to my media or burning process?
Thanks for any help, and sorry if this is something that should be obvious - I'm completely new to burning DVDs.

Computer: G4 iMac, 10.3.8
Media: Memorex 8x DVD+R printable
Burned as: Data DVD using Toast 6 Titanium
Burner: NEC ND-3520A in a BYTECC FW enclosure
http://www.newegg.com/app/ViewProductDesc.asp?description=27-152-035&depa=1

[newnews]

what setting did you use when burning DVD? It should be ISO mode and no multisession

[junkmalle]

Overheating?

[cattrfly]

what setting did you use when burning DVD? It should be ISO mode and no multisession

I really have no idea - I just threw the avi files into the Toast "Data" window, clicked the radio button for "Mac & PC compatible", and cooked it. Is there a way I can check the formatting of something already burned (Mac OSX)? But if there's something wrong with the disk I would think the problem would show up as soon as I insert it into the player, not only after a period of time.

Overheating?

This seems a bit more likely to me - the player is sitting on top of my other DVD/VCR combo player, though they're never in use at the same time. I guess I'll try moving it and see if that helps.