eh, i am using sbox, but i have sent it to change to the internal neo2.5 mod chip instead. but i'll just share my part on starting my game

i am using the PAL 30004 R PS2
with sbox and AR2 Version 2

what i did was this

Power on the PS2, put in the AR2 Boot disc...select all the codes that u need, if your games does not need any codes, select no code...
and when you come to the screen that ask you to put in your game cdr, eject the boot disc, switch on your sbox, put in your CD and close it...wait 4 to secs then press X...it should load up.

It works perfectly for me, but i don't know if it will work for you, but can always give it a try

Cheers