When you run a PS2 disc on PS3, sometimes it exits with an error code. Here there are some:
80028F17 - booterror
80028F18 - unsupported disc; eg. Utility discs, BB discs, IQ Remix game etc.
80028F19 - fsck; the internal PS2 disk got corrupted and I guess that you can use HDD utility disc to fix it
80028F1A - invalbnnetcfg; network config error