Pingbacks won't work with PHP 4.2. opensocket() implementation seems to be buggued in PHP 4.2. Pingbacks work fine with newer versions of PHP.
Please note that pingback implementation itself was buggued in b2 but has been debuggued in b2evolution. more »
b2evolution (as all other b2 versions) does not currently implement database transactions. This is due to the fact that mySQL has not been supporting transactions for long enough by now to assume they are commonly available on hosting services.… more »