It means that somehow "emptyenum" got defined twice. You can search the code for that string and see if you can figure it out.

I suspect that there is either something unusual about your usage, or you have a messed up installation. But I don't know as I no longer use Windows.

If you can't figure it out on your own, you could post to Seekers of Perl Wisdom and see if anyone else has seen this error. (Replies in buried threads are unlikely to be seen and responded to...)