Remember that for CPC it needs pretty low level access. That is why CPC games do not work on modern Windows. I would suspect something wonky with the floppy drive. One other possibility is a corrupted game file that copies the file without CRC errors. Check the contents of the AGI, CPC.COM and AGIDATA.OVL. You can compare it against an AGI game that does run.
Also try the AGI Disk Free! Decryptor. It won't modify any of the files, it just writes a replacement launcher (AGI.EXE). You will have to do that under Windows, but you can just drop the new file in the game's folder on your DOS machine and start the game with it. If it runs then something about that drive does not like the "bad" track or a corrupt AGI or CPC.COM files.