Thanks for the test.
How can I get that version of CVX? Previously I downloaded from http://cvxr.com/cvx/download/, but cvx_version told me that it is v3.0 beta.
Update:
Interestingly, the .zip package is v3.0 beta, while the .tar.gz package is v2.2 for win64.
Update2:
Seemingly that does not help. Maybe it is because of my Matlab version being too old?
Update3:
The problem is solved by typing clear all and rerun the script. This ad-hoc solution is from http://ask.cvxr.com/t/error-function-subsindex-is-not-defined-for-values-of-class-struct/3803.