Thought the following would be useful to help in debugging.
$ ruby --version
ruby 1.9.3p194 (2012-04-20 revision 35410) [x86_64-linux]
$ gem list
amazon-ec2 (0.9.17)
aws-sdk (1.38.0)
builder (3.2.2)
curb (0.8.5)
daemons (1.1.9)
eventmachine (1.0.3)
json (1.8.1)
mini_portile (0.5.3)
mysql (2.9.1)
net-ldap (0.6.1)
nokogiri (1.6.1)
parse-cron (0.1.4)
polyglot (0.3.4)
rack (1.5.2)
rack-protection (1.5.3)
sequel (4.9.0)
sinatra (1.4.5)
sqlite3 (1.3.9)
thin (1.6.2)
tilt (1.4.1)
treetop (1.5.3)
trollop (2.0)
uuidtools (2.1.4)
xml-simple (1.1.3)