I just did a quick search. When are you trying to book reservations for and for where? I put in 2 adults and 4 chidren (10, 8, 6, 6) just for a test and picked a moderate resort. It bumped me up and gave me prices for either the Fort Wilderness Cabins, Saratoga Springs or Old Key West. Didn't say anything about needing to call. It let me go through to the confirmation page, right before you buy. Maybe the resort you are trying to book doesn't accomodate 6 people?
Gail
80 & 91 WDW OffSite; 10/95 DL Honeymoon; 4/00 & 5/01 DL Off Site; 12/02 WDW - ASMo;
10/03 WDW - CSR; 5/05 WDW - ASMo; 2/07 WDW - SSR; 8/07 WDW - Pop - Me & DD;
1/08 WDW - CBR - DH & Me; 8/09 WDW - THV & SSR; 08/11 WDW - Pop w/Free Dining