Your error message is as a result of having a comma in 100000. Therefore, MATLAB thinks you have provided 3 arguments, when it is expecting only 2. Never put a comma in a number in MATLAB.
However, even though after this fix your code might now wotk without error message, it doesn’t seem to match what you wrote above. I’ll let you figure out what you really meant.
If your constraint above is correct, I think you need something more like
-rel_entr(1-tau,1-tau + 100000*h(k)*p(k))/log(2)
See my answer at Writing a constraint in DCP complient format (note that mcg’s typo was fixed subsequent to that post).
Because I’m tired, I may have made a mistake, and you should check if this is correct.