Hi Ed,
At this point, your problem looks like isolated to your computers at home or your internet connection.
1. I have seen cases where your internet provider blocks specific ports. If you have access to a free internet somewhere, you can try connecting from there.
2. Looks like there is another port that the DVR is using aside from your connection port 50000. If you can tell me the brand of DVR that you are using or PM me a manual of your DVR, maybe I can figure it out
edselrt