It is a well-known fact that some PS2 games needed a patch in order to get the backup working with Swap Magic. These games were mostly games developed by EA.
I also remember that games stored on Dual Layer media cannot work with Swap Magic - unless you've got hold of an original PS2 game that has a TOC that tops 8 GB (for the Swap Magic TOC Refresh Mechanism).
But I don't know anything about these two particular games. Maybe you'll have more luck over at the ps2nfo.com forums.