The classifieds requires a separate registration, most of us use the same username and password there as we use in the forums to keep things simple.
Quote is from the top of the page in the Classifieds:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">iRV2 RV Classifieds
*** Please Note, the RV Classifieds requires a separate registration from the forums. Once registered, you will be able to access the photo gallery and campground reviews with this same registration.
'11 GMC Acadia SLT AWD
'11 GMC Sierra 1500 4x4 Extended Cab