Unfortunately, PlatformPro is now a deprecated product and many of us don't use it anymore. I concur with Danny, you should really upgrade promptly, as each WordPress update places your site at greater risk of crashing. No further updates to PlatformPro will be forthcoming, so if it crashes, we won't have a solution.
Meanwhile, PlatformPro does have Meta Settings on each page. If you go to Dashboard > Pages and edit the pages where bbPress appear, scroll down to see PageLines Meta Settings. If you do not see this option, please go to the top-right, click Screen Options. A panel will descend and the first option should be PageLines Meta Settings. Make sure it is checked. You just close the panel by clicking Screen Options again. Scroll down, and the meta settings should appear.
Thereupon, you should see under the General Page Setup tab the drop down list which allows you to make the page full width. Select that, save the Page. Now, the bbPress page should be full width, without sidebar. You may also, optionally, use the PageLines Sections Control Panel, on the edit page to "Hide Primary" sidebar (and/or any sidebars selected in your layout). Check that and save.
Unfortunately, support for PlatformPro is extremely limited at this point. Danny was also correct in saying that PlatformPro has not supported any bbPress since bbPress 2.x came out. There is a compatibility issue which is unsupported. The only solution is upgrading to PageLines Framework.