You can't play PS1 games with a swap magic disc. Use this method instead (it works with an NTSC PS2, I assume it would work with a PAL one also, but I don't really know).

1. Go to the PS2 dashboard/browser so that you can see what disc is in the drive and what memory card is inserted.
2. Insert a legitimate PS1 disc, close tray.
3. Once it recognizes the disc is there, use the slide tool to open the tray, put in Chrono Cross, then shut the tray and lock it with the slide tool.
4. Boot.

This works for burned PS1 games, but I don't know if it would have any effect on region-coding. If it fails, try downloading a PAL copy of Chrono Cross so you can play it, if that's what region your console is?