How do I go beyond the SLED ON step of the S560D drive auto adjustment?

Does any one remember the solution for the ‘NO DISK’ problem of the SONY S560D?
I already ran the DVD SL DISC calibration procedure (in the DRIVE AUTO ADJUSTMENT menu), however, after a ‘check focus S- level’ request in which I chose the OK option, the procedure leads to the following error:

DVD-SL DISC
Error!!
Adjustment Quit
Sled on
Jitter FF
SA.-----SI,-----EMG. FO


How do I test the status of the 'focus S- level' signal. Is it the reason of the forthcoming sled on error? How do I go beyond the sled on step?

Thanks in advance!!