I have installed Hamachi for VPN use but my ESET Smart Security 4 doesn't allow communication to Hamachi. The Hamachi is xttp://cid-8ac728c8703bfe0f.office.live.com/self.aspx/Software/Hamachi.zip
Ohhh boy. Forget about this link, use this instead. https://secure.logmein.com/products/hamachi2/ Regards.
If you have ESS set to work in automatic mode (default), switch it to learning mode. Otherwise I'd suggest removing any existing rules to switching to learning mode to ensure to ensure that no blocking rule for the communication is already created.
learning mode http://kb.eset.com/esetkb/index?page=content&id=SOLN2118 and on deleting custom made rules http://www.eset.com.sg/html/167/605