I have a launch PS3 60GB from launch and it works perfectly with GTA4. What may be the problem is faulty game save information. Delete all game save folders and the install data for GTA4... Then turn off the autosave feature in GTA4 and it should work.
Give that a shot before sending in your PS3. I'm sure a future patch will fix that issue.
My pokemon brings all the nerds to the yard. And they're like, "You wanna trade cards?" Damn right, I wanna trade cards. I'll trade this, but not my charizard.








