Took five seconds to search Google groups.......

From the Pioneer knowledge base:

Why am I getting the following error message, DVD key exchange for copy

Sonic CinePlayer does not currently support playing a DVD-RW disc with the
Content Protection of Recordable Media (CPRM). CPRM is a newer copy
protection scheme developed for broadcasts so that a transmitted video
sequence can only be recorded once and not copied. Pioneer's DVR-A05 is one
of several newer devices that recognizes CPRM-capable DVD-RW discs. However,
Sonic's CinePlayer does not recognize CPRM technology thus gives the key
exchange error message. This message displays even if you have not recorded
a CPRM broadcast onto a DVD-RW. To avoid the problem, use DVD-RW media that
does not support CPRM or play the DVD-RW with CPRM on another DVD playback
application. However, the Pioneer DVR-A05 can interpret CPRM media.