So, what is the solution to remove Secure Spot. I have the DIR-625 and it is blocking my machines from the internet. 
Reportedly, D-Link is working on a firmware upgrade that won't contain SecureSpot. Until then you can either keep switching SS off, or simply disconnect the router from the internet and use one machine for internet access.
To switch SS off temporarily, go to the router control page with your web browser. (This is from memory, since I've disconnected my D-Link router, so I may get a step or two wrong, but you'll be able to figure out what to do.)
- After you log in as Admin, click on the "Advanced" tab, then "SecureSpot", low in the left-hand column.
- If "Enable SecureSpot services" is checked, uncheck it and click "Save Changes". You may have to wait for the router to reboot.
- If it is already unchecked, check it, click "Save Changes", wait for the router to reboot if necessary, then go back and uncheck it, and save your changes again.
This will turn SS off until you cycle the power or reboot the router, or until the router decides again that you need to pay for unnecessary security services.
A representative of D-Link finally replied to one of the many threads on this subject, saying that the problem arose when BeSecure.com (the "service" provider for SecureSpot) changed the address of its servers. What I make of that is that when our routers phone home (did you know they were checking in with SecureSpot, even if you've supposedly disabled it?), they don't get the response they expect (such as "This user has declined to buy SecureSpot services, so let him browse the web;") and so try to force you to buy SecureSpot services. But since the server has moved, all you get is a "Bad request" error.
Didn't anybody at BeSecure tell the people at D-Link they were going to move their servers? Didn't somebody stop and think that that might affect the behavior of routers that secretly check in with those servers? Sheesh! What nincompoops!