According to Avira antivirus:

C:\Documents and Settings\jonw\My Documents\Installs\InstantRails-1.3a-win.zip
[0] Archive type: ZIP
–> InstantRails/ruby/bin/ruby.exe
[DETECTION] Is the Trojan horse TR/Spy.Ruby.Ka.2.C
–> InstantRails/ruby/bin/rubyw.exe
[DETECTION] Is the Trojan horse TR/Spy.Ruby.Ka.2.A
[INFO] The file was moved to ’451431cd.qua’!

I don’t know what’s up with that.