Recently, there is a new update to v4.12, but it appears that many people are having issues installing it. The main culprit is the VC++ Redistribution library download and it looks something like this:
Basically, even if you updated your VC++ Redist manually, the download will still happen and likely fail again and again. To overcome this, Sandboxie actually had setup standalone version of their installer and it will solve the problem, but I still strongly suggest you update your VC++ Redist manually first before downloading this and running it.
Get the standalone installer of Sandboxie here:
http://www.sandboxie.com/index.php?AllVersions