FileForums - Cannot Copy mdf files to HDD

OK this may sound strange cauz it does to me aswell ... i cannot copy the image files of the star protected game DvDs. (e.g Splintercell - Chaos Theory and Prince of persia - the two thrones).
Even though i hav more than 20gb of HDD space empty ... yet wheneva i try to copy the .mdf files (around 4.smthing gb in size) i get the error "THERE IS NOT ENOUGH DISK SPACE" .... tried searchin for it but could find ne answer.
I have tried 2 different DVD-roms and 3 different Op. Systems ... all givin me the same pbm. (on the other hand it copied without ne pbm on mA friends system).

so the next thing i tried was i zipped the file to mA hdd ... which completed without ne errors ... but now when i try to extract the file i get this error ....
..... "Disk full or system limits exceeded" ....

The last resort was to boot the system with a Bootable DVD ... which i did .... but in dos the DVD isn't readable ....

I m sort of goin crazy as to whts goin on.

NOTE 1 : THERE IZ NOTHIN WRONG WITH THE DVD CAUZ MA FRIEND HAS SHOWED ME COPYIN IT TO HIS SYSTEM AGAIN AND AGAIN WITHOUT NE PROBLEM.

NOTE 2 : I CAN INSTALL THE GAME DIRECTLY FROM THE DVD WITHOUT NE PBMS BUT THESE TWO GAMES REQ. OPTICAL DRIVES TO BE DISABLED FOR PLAYIN SO ........

MY SYSTEM'S SPECS ARE ....

P4 2.4ghz (533 bus)
intel GBFL (D865) (motherboard)
1 gb DDR
2 hdds ... 1 40gb seagate (normal IDA drive) and the other 200gb Sata (seagate).
DVD-writer (samsung)
DVD-rom (sony)
Nvidia Geforce FX-5200 (128 mb AGP(slot) 3d-card)

Op. SYstems
2 windows xp pro and 1 windows 2k pro
partitions 12 (6 on each drive) ...

PLzzz help me out ...