Unable to play PS2 DVD-R games

[nickw]

First thing - I've read several FAQs, trawled forums and done internet searches, but am still stuck.

I have just had my PS2 chipped with a DMS3 and am unable to play "backup" games.

The problem is that I am unable to play backup games and I get the red screen of death when trying to boot downloaded games.

My PS2 still plays "normal" games and the chip-installers have assured me that they fully tested my PS2 with a copy game before shipping back to me. Unfortunately, I don't have a known good backup game to test with.

I am using a Sony DWU-18A DVD-Writer, Panasonic DVD-R's and Nero 6 (at 4x).

Please could someone give me some pointers for trouble-shooting and/or what I am likely to be doing wrong.

Note: the games are downloaded from a good source.