[Mark]

Those are warnings, not errors. They are only presented when E_STRICT is on, as the PHP engine can and will disregard them and continue to compile just fine. Without looking into the problem too deep (it’s getting on, and I’m about ready for bed), off the top of my head I would suggest that the deprecated warnings are due to the fact that PHPs handling of OOP has changed mildly between v4 and 5. Objects are now passed by reference by default, whereas in PHP4 they weren’t. Since bbPress is backwards compatible to work on PHP4 (it cuts down on the snarky accusations that one might receive for being version specific), it will return warnings in PHP5 that are just that. Warnings.

That’s the only real problem too. Turn off E_STRICT and you won’t get the remaining notices. The ‘headers already sent’ errors are due to the fact that you’re getting the deprecated warning (which outputs text to the screen, thus sending headers) before the script has completed its run.

So… simply put, it can be called stable, as it’s purely your setup that is causing the issue, not bbPress itself.