dvdrs not reading in portable player

[koinhelgo]

I have copied some DVDs to DVD-r - using both smartripper and dvddecrypter to rip files to HD. Used DVD shrink to reauther smartripper files and burn to DVD-r and used whole disc mode to burn dvddecrypter files. Both sets of files didn't need compressing. Also have used dvdclone to make a DVD-r of one.
Now these DVDrs play fine in my pc and standalone player but my portable DVD player sees them as CDs and won't play them. The portable plays DVD-r movie back ups from other sources fine. I have tried copying one of these directly to another DVD-r and the player won't play that either.
I thought it could be a media issue and have tried various types (including some DVDRWs) and at all different burn speeds but none play movie files on the portable. I have even burnt a DVD-r using my burner that contains MP3s only and the portable player reads and plays that fine- so it looks like it aint a media issue.
A friends portable player reads the discs and plays the movies OK.
Am I just destined to not get the portable to play DVDr movies that I burn myself.
The only thing I haven't tried yet is DVD+Rs but I have ordered some to try them.
Would getting another program to copy the discs help. I am even thinking of buying another burner to try out.
Off topic - If DVD Rom drives are better at reading discs than Writers how come my writer rips at up to 9.5 times and my supposedlty 16x Rom drive only at 2 times. As far as I know the writer is the primary master and the rom the slave. If I get a new burner would this be quicker even if it is set up as a slave.
Regards

[zworg2]

See Number 2 HERE

What type of media have you tried?

Any other specifics you can give?
(nice post but NO details)

Filling in your PC etc details in your profile would help.....

[koinhelgo]

Ok here goes
I've used Verbatum, datawrite 2 different kinds one a 2x and another 8x, two unbranded ones which I think are by Ritek and ones by Ri-disc. All are DVD-r or DVD-rw.
Using a new pc so haven't updated profile, running XP SP1 Athlon64 3000+ with 512 meg of ram. Burner is an Artec VOM12x48 - latest model and latest firmware available. Rom drive is also (I think) an Artec but doesn't give me any clues even using Nero systeminfo tool or DRVinfo. Using latest DVDDecrypter dated 5-1-05. Don't know the DVDShrink or CloneDVD versions - I can't find out cos I'm at work at mo. Running NERO 6.3.
I read Number 2, but I've tried the suggestions really- as I say the movies play fine on my normal standalone (not just my pc) and on a friends portable. My portable plays other movie DVD-Rs I have got from other people (some on same media as I have tried Datawrite and as far as I know created with DVDShrink). It also plays an MP3 DVD I burnt on the Datawrite media.
Regards