Plextor error

I burned a few CD images (got it from the net) to CDR and when i check for
C1/C2 errors, in all such CDR's i ge error code 30600 - medium error. In
help it only says "no reference position found". It shows it after it has
finished checking, and there's no CU errors and very few C2 ones. CD is
readable perfectly.
I wonder, what's up... If i extract same image (using WinIso) and burn it
such that i add extracted files to ISO compilation, there's no error.

Info: Plextor Premium and XP Pro, Media Sony 40x and Fuji 40x. also one CDR
is Sony24x, made from TY - same error.