another person who has problems with zones (sigh) I've lost count of all the posts about people and their zone problems
did you also setup your speaker configuration as F or G for 5.1 systems?
F: 5.1 biamp + zone 2
G: 5.1 + zone 2 & zone 3
because if you left it at the default A: 9.2 setup, you will get nothing from the speakers plugged into the surround backs in zone 2. because they in the default configuration, surround back terminals are for rear channel speakers in a 7.1 or 9.1 setup in the main room.
did you connect your sources with analog l/r cables in addition to HDMI or digital cables? because for true multizone use (as opposed to B speakers in another room), these receivers do not convert digital & HDMI to analog. you must also connect analog connections for multizones, pg 35 in your manual I believe.
did you try using the remote button marked SIG SEL to select the analog connections? by default, it's set to Auto with the connection priority being HDMI>Digital>Analog. so if Auto gets you no sound or you have both digital & analog connections, it will not select the analogs in Auto. you should manually select Analog using that button for whatever source you are using, with the exception of course of Internet Radio, Pandora, Media Server (internal networked sources in the receiver).
did you try using the front panel or remote multizone buttons? especially if you want a different source than main room.
now if you don't want to bother with analog cables OR don't need the ability to have independent sources playing at the same time in 2 rooms, then you can just go with a Speaker B configuration, Speaker Configuration B: 7.1 + B Speakers. then use the SPEAKER button on the remote to select A, B or A+B speakers. also in your manual, pg 74. for B Speakers you'll also need to connect them to Front Wide terminals, instead of the Back Surround ones as shown in the manual.
as you see, there are several ways to do zones & how they work & buttons to use all depends on which way you choose to do them. that's why it's difficult for someone in a forum to give you the
answer...we don't know what you did, how you connected things, and what things you have setup in the menu or not setup, what buttons you've tried or not tried. reading the manual thoroughly is an important step for setting up zones because there's some nuances & subtleties that are not obvious but the info is there.
try the above. but I second calling Pioneer support if you still can't make it work because it's a setup problem.