ok: i found out something.
the error is in here
function maybe_unserialize($original) {
if ( is_serialized($original) ) // don't attempt to unserialize data that wasn't serialized going in
if ( false !== $gm = @ unserialize($original) )
return $gm;
return $original;
}
if I comment the “return $gm” line the error disappears (but wp crashes when looping the posts, obviusly).
someone can help me?