Error running stan

[TerrySnow1963]

Hi , I am doing the current edX course and am trying to compete this exercise.

My apologies, I am a relative newbie to R, so may be a basic R issue.

When I follow the code, I get the following error when I try to call stan:

define BOOST_NO_CXX11_RVALUE_REFERENCES

      ^

:6:9: note: previous definition is here
#define BOOST_NO_CXX11_RVALUE_REFERENCES 1
^
1 warning generated.
Error in .Call(Module__functions_names, xp) :
negative length vectors are not allowed

the 'fit' variable is not defined.

Any suggestions ?

Additonal info: I am running RSTAN on OS X 10.12.4, have just update Xcode.