Downloaded the installer for STS 3.3.0 for Win7 64bit. Immediately failed saying JRE 1.6.0 was required. I then downloaded the ZIP version, unzipped it and it starts fine. I also noticed in the STS.ini file a line reading: -Dosgi.requiredJavaVersion=1.6
Is it possible that this line causing the install to fail or is there another issue with the .exe file? I noticed also that there was a similar issue with the 3.2.0 version in a thread from "Forum->Spring Projects->Spring Tool Suite" on April 9th, 2013 where Martin Lippert mentioned that you would look at the installer issue...I haven't seen any resolution for it, however.