Man, you can try go to the Gemfile.lock e look for those lines:
riddle (1.5.0)
thinking-sphinx (2.0.5)
activerecord (>= 3.0.3)
builder (>= 2.1.2)
riddle (>= 1.5.0)
If you read again the error you will see that is the Riddle launching error not sphinx.
*undefined method `indexes' for #<Riddle::Configuration:0x41b57b0>*
I have a project working perfectly with thinking-sphinx 2.0.5 and in the Gemfile.lock the sphinx is requiring the riddle version 1.3.3 or older so in the project that the same thinking-sphinx isn't working I changed my riddle version in gem file from 1.5.0 to 1.3.3 using thinking-sphinx 2.0.5 and the problem was solved. The sphinx version 2.0.10 works fine with riddle 1.5.0 so you have to choose if you want to change the Thinking-sphinx Gem version or the Riddle version on Gemfile.lock to:
riddle (1.3.3)
rubyzip (0.9.4)
thinking-sphinx (2.0.5)
activerecord (>= 3.0.3)
riddle (>= 1.3.3)