Panasonic SC-HT540 Will play shop DVD's but not any copies, although the same films will play on other machines of better or cheaper quality.
This is because Panasonic devices are PICKY about media.
Get better media for your copies…
Try some Verbatim 16x media burned at 8x or 12x speed. If your burner can bitset +R disks so that they look like DVDRom disks to the player, do that. If you don’t know if it can, get the -R disks instead.