Shadow Hearts, the gods they are against me.

So, about a year ago, I bought a used copy of Shadow Hearts: Covenant at my local Gamestop.  The disks looked fine, had the manual, and original case.  A good deal, actually.  I didn't play it at the time, because I also bought like 14 other PS2 games, and just stuck it in a drawer to be played sometime in the future.
 
Well, about 3 months ago, my laptop was getting repaired (took about 2 weeks) so I figured it was time for me to dig up SH:C and give it a go.  I know it's well regarded (in it's day), and I was curious.
 
So, put the disk in my system, started the game, and my PS2 just showed a black screen, for like 5 minutes.  
 
I should divulge that my PS2 is soft-modded.  Specifically with the FMCB package, including HDLoader.
 
So, thinking the mod might've caused the problem, I removed my memory card, and tried again.  Now I got no black screen at all.  When I select the game disk from the PS2 menu, my disk drive makes a click, click sound, and just dumps me back to the main menu.
 
Thinking it might be the game disk's fault, I cleaned it off, tried it again, got the same result.  I then tried installing the game to my PS2 hard drive, via HDLoader, and it installed fine.  I booted the game that way, got about 4 minutes in (hit the first battle) and the game froze.  Apparently, it's one of the few games that HDLoader doesn't support.
 
About a month went by (got my laptop back in the mean time), and I found another copy of the game for sale online.  I managed to snag it (for like 20$), tried it on my PS2, and got the exact same results.  So....think it's safe to rule out the disks being at fault.
 
In further support of this is, I tried both disks on my laptop via the PS2 emulator PSCX, and both copies booted, no problem.  I can't play the games on my laptop, because the speed varies heavily, but I could at least get to the main menu.
 
So, I posted all this info on a msg board, and one person suggested using a "clean" install of the game to HDLoader.  Basically, installing the game from my laptop to the hard drive, because there's something wrong with the laser in my PS2.
 
Well, I did that.  Connected the drive up, made an iso, copied it into HDLoader just fine, etc.  Booted the game back up with HDL, and started playing.  I got about 20 minutes into the game, hit the first boss, and killed him.  RIGHT at the treasure/exp screen, the game froze again.
 
The gods, they are a laughing at me.
 
In a few days I plan on grabbing another PS2 (from Gamestop) and beginning the process all over again.  Should be a headache-inducing adventure.