Could you look at this question, because I think I have uncovered a bug.
I have defined a JME extension function loc(A,B,C) -- to solve the law of cosines for the the angle opposite side A.
I use it three times to find the angles of a triangle with sides A, B and R.
thetaA = LOC(A,B,R)
thetaB = LOC(B,A,R)
thetaR = LOC(R,A,B)
All three produce "Error computing referenced variable c".
If I define a dummy variable C it eliminates the error, but I don't think I should have to since the names of the parameters should be immaterial. I just noticed this problem. I don't believe it happened when I wrote the question three years ago.