Help with DVD decrypter

[T3]

I have a set of 4 DVDs (1hour continunig footage each) and i would like to make copies. I try using DVD decrypter and at random points it fails with a I/O error. I dont think its any scratches on the disk because it happens on all four DVDs all at random points (i.e 30%, 55%, 99% etc). I also try using DVD shrink and still it has problems.
When i try any normal movie - it works fine. So that eliminates the fact its the DVD writer(NEC1300). I have also tried on my other slightly lower spec PC and it has same problem there too.
The DVD is not encypted - so if i was to do a straight copy (i.e file copy in explorer) would that work ?
I need to cpoy these DVDs as these are a master copy and i do not want to use these often.
Also - is there anyway that i can compress the 4DVDs to sit on 2DVDs - with compression.

My spec is as follows:
P4 1.6Ghz
1024Mb Memory
NEC ND1300A DVD writer
Windows XP Pro

Any help would be greatly appreciated.
Thanks

[poopyhead]

if these are not encrypted, then just copy over the VIDEO_TS folder from the DVD to your hdd using windows explorer and burn.

btw, you should really get a cheap 16X DVD-ROM for ripping and reading DVDs.

1) most DVD burners are locked at 2X ripping speed

2) ripping and reading DVDs will increase wear-and-tear of the drive..so, it'll be much cheaper to replace a dead DVD-ROM than a DVD burner