Ok first what Version or Model number PS2 are you using?
I am thinking if you are using a Slim PS2, your not using the Tools or sensor mod correctly.
For PS2 Slim
Open the disc door and remove Magic Switch ?Tool A?, replace CODER disc with larger TOC size disc, then reinstall Magic Switch ?Tool A? *(Caution: the disc will start spinning once the ?Tool A? has been reinstalled).
When the TOC refreshing finished, the disc will stop spinning and a scrolling text will tell you to swap your own program.
