Sorry if this is inappropriate to ask on meta, but back in April I updated an old answer of mine that is over two years old here, on the existence of a zero sum subset problem. I suspect due to how old this question is, no one has even noticed that I updated my answer.

I believe I have given a correct solution, but being as I am not a professional mathematician, I have been unable to find a qualified person to check it for me. If anyone would be willing to give some feedback it would be much appreciated.

Thanks!