[Plugin: bbpress] Incompatible With a Custom Theme?

I have bbpress installed on my website with a custom theme and topics and forums appear perfectly yet if anybody replies to a topic it does not show up. Also editing topics just takes you to a blank page. After disabling all plugins nothing was fixed but changing to the Twenty Twelve theme fixed it perfectly. I need to be able to use my custom theme, however, so how can I make it compatible?

I could only find one answer to this question when somebody else posted about this but the topic was closed after somebody said to look through the php files and copy over some parts from a compatible theme into the incompatible one’s functions.php or page templates. It was not very clear to me.

I am very much a newbie at php and I can only edit very simple things, so what I really need is somebody to tell me which line I should edit and what value I should put in it.

So far what I understand from the other theme is that I should edit the page templates. I don’t know which line I should edit and what I should change it to, so any help with that would be great! Also I want to preserve what my theme actually looks like if I can, while still providing compatibility with bbpress.
Sorry for the long post and I hope I get some answers!

Thank you!