Download something like DVD Decripter. It's a closed project but google it and you'll find it.
Open it up. Then put in the ps2 disc and go to Mode -> ISO -> Read. Once that's done, take out the disc and put in a blank DVD-R and go to Mode -> ISO -> Write. Be sure to select the ISO file and not the other one that was created. Once done you should be able to play. If you downloaded an ISO, you should just have to write it onto a blank DVD-R disc.