If request sits in shared folder it should be namespaced Shared::Request (not sure if that solves the problem to explicitly require it. but it might, have been trying to google and find a link, couldn't find a useful one)

Also I see you have multiple things of type report and requests
it would be better to place them in 
request and report folders rather than folder technical_fault_report
and use namespace Request:: or Report:: 
http://rails-bestpractices.com/posts/74-namespaced-models (point 2 miht be helpful)