Here is the link to the user manual for your player if you need it;
Page 38 of the manual (page 42 of the pdf file) describes the error codes
error 6 states "a disk is loaded upside down inside the cd deck and doesnt play properly"
Suggested solution is to try the disc the other way up, if this doesn't help then there is most likely a problem with the lens - possibly cured by cleaning, please ask again if you want to try this yourself and we can talk you through it
pls - check also that the cds you where trying to play were of the correct type, and burned in the correct format, also that the settings are correct for the type you are using - page 21 (25 pdf)
Next thing to try is cleaning the lens - use a cotton bud which you have dipped in alcohol - rubbing alcohol is ok - but let the cotton bud dry mostly before going at the lens.
Figure out how to get to the lens and very gently wipe it with the cotton bud.
Remember the lens is not that scratch resistant, and it is quite finely positioned, so wipe, dont scrub.
If that doesnt help, then check that there is adequate voltage to the unit - it may have enough to appear to function but not to initiate the laser - bad ground cable would be the first suspect.
If no luck with that, then i think the set needs to be serviced properly - sorry
if you need help finding a service centre let me know with your general area
Hope this be of initial help/idea. Pls post back how things turned up or should you need additional information.
Good luck and kind regards. Thank you for using FixYa.