I am getting the same parse error on my IPad as well. I installed updated Forum Runner software I still get it when accessing TBN. I do not get the parse error while accessing other forums. Note that I can still see the threads that I have subscribed to but I can not get to "current" or "search" parts of the forum when using the app. I had to use google to find that the issue was not with my IPad and Safari to get this posted.
Edit: I poked around on Forum Runner at various other Forums and found most did not have the parse error, but a few did.