Invalid "no such file to load" warning

RubyMine 4.5.4 is giving me "No such file to load" on my require 'spec_helper' statement and has it underlined in grey.

My rspec examples run fine despite the warning.

However, if I comment out that line, then my examples fail to run, because they cannot find a dependency which is specified in the rspec_helper file.

Any thoughts on why RubyMine would be giving this warning when the file can clearly be found by Ruby?

Thanks,

Wade