Getting this now:

Critical error – bailing out

This is an error that has been elevated to critical error status because it occurred during the primary error mechanism reporting system itself (possibly due to it occuring within the standard output framework). It may be masking a secondary error that occurred before this, but was never output - if so, it is likely strongly related to this one, thus fixing this will fix the other.

PHP ERROR [1] Call to undefined function get_version_dotted() in sources/failure.php on line 875

Details here are intended only for the website/system-administrator, not for regular website users.
» If you are a regular website user, please let the website staff deal with this problem.

Is this Beta1 or Beta2 because Beta2 should have fixed this and is available for download now.