I have an LG LHX-557 that when i go to play a disc it will show "READING" on the screen of the player. After about a minute or so it will stop and say disc error. I have tryed this with all 5 trays of the 5 disc changer and with several correct dvds or cds. It will not play.

SOURCE: LG DVD player Disc Error message even when playing lens cleaners!

LG DVD Player Disc Tray opens & closes automatically & unnecesarrily

SOURCE: "Disc Error"

Try lens cleaner hope it will works.

SOURCE: I have an LG HomeTheater

In the past this has been caused by the laser not reading the disk. This can be caused by either a dirty laser or disc as well as an unformated disc. Most likely your laser is getting weak and is not picking up the info on the disc. I have solved this before by opening the cover on the dvd and simply unplugging the ribbon connector from the circuit board to the laser, leave it unplugged for several minutes before re-connection and then try to use the dvd again. This may clear it up and it may come back. Short of replacing the laser unit in the system, this might help for a while. If this continues and does this on a variety of discs not just one, then you need to decide if you want to spend money on a repair or replacement. If you wish to try and replace the laser that can be done also, but if it were me I would save my money and get a good quality player and you will get a warranty on a newer player. I personally use Sony and have had very good luck in these units. You can also run a cheaper dvd player through the theater system by hooking it up as an outside component thought the audio video jacks on the system.