JDM units often have region locks or GPS issues outside of Japan. A "BETTER" manual typically includes troubleshooting sections not found in the original paperwork, guiding you on how to bypass region locks or reset the GPS positioning for your local area.
To bypass the DVD lockout (so you can watch a DVD while driving—for off-road use only, of course), the BETTER manual provides the exact sequence: Pioneer Carrozzeria Avic-rz500 English Manual BETTER