Hi everyone,
Please give the latest AMXX snapshot builds a try (hg29 or later) and let us know how they are for the beta. It's still a bit of a work-in-progress, but these builds should fix the crash when players join the server as well as the hamsandwich issues. Let us know if there are any other problems.
Also please note that third-party modules like Orpheu and Rage or plugins that require them will likely need updates from their authors (for signatures and/or offsets).
http://www.amxmodx.org/snapshots.php