Some recent updates used the double quotes " instead of the simple quotes '.
New versions of MATLAB interpret this as a string object, but the older versions make the parser crash.
I fixed the code: https://github.com/brainstorm-tools/brainstorm3/commit/f6455f4161fa92aa5b27dfc64800694262cb51bd
Please update Brainstorm and try again.
@Anand_Joshi FYI