I can answer your problem which it happens to me also.
Sandboxie must be update if a new software will be installed on your system for compatibility. Like Browsers and Antivirus.
Like what my experience forgot the exact version of mine.
Example:
Sandboxie 3.4X will not work of FF 8 and avast 6.0.1367.
Try it =)
Sandboxie is a very low system requirements it even run my amd sempron 1.60 ghz, 512mb ddr. 32 bit Videocard.
Well the latest version is 3.62
Btw im using 3.60 but after i go home i will update to 3.62.