ive sent my ps3 into sony 3 damn times and still aint working, ive decided to ask real people that know what they are talking about. (instead of a loser on the phone sitting on their butts the whole day)
The first thing that pops into most people's heads when they hear freezing with original discs is either if the disc is scratched/dirty or the PS3 laser is... did you try another PS3 game on the same PS3 console and it works fine, only GTA4 freezes?
i believe i read something about this stating there was a bad batch of discs, they worked fine on the 80gb sku but are having issues on the 60gb one. I'll try to track down the source of where i read it and post back here if found.