Well i wish ya luck and i hope you get it to work.:)
I would try these things:
-Clean the ps2 lens
-make a new uLaunchELF iso & burn to CD or grab one from the uLaunchelf thread
-Keep the files on the USB stick and be sure it in the console before turning it on.
Get a backup USB stick, just to be sure you have a compatible one....a different brand if possible and formatted to FAT32.
This is your best chance for an install to go right.