jerry23,
1. autosandbox/sandbox/safezone components have NEVER worked in WinXP 64-bit (virtualization driver isn't loaded on this OS, because WinXP 64-bit is old system and it doesn't contain several internal libraries which are required by our sandbox)
2. prior to build 1203, all avast versions contained a bug in UI where you saw autosandbox options even for WinXP 64-bit OS -- please note, UI is separated from avast components (UI just sends commands to the components to do a work - it's only a thin communication layer; for example, when UI in 1203 sent autosandbox's commands to this component, they were never completed, because this component was missing on this OS)
3. so, if you got an autosandboxed popup in UI, it actually never worked, because the main autosandbox component was missing and not working on this OS