If you disconnect the router temporarily
, and then try to connect, you'll know for definite if it's the router or not. This just clears this possibility out of the way to make it clear for all of us.
Make sure your ISP hasn't got you firewalled - the only way to do this is to phone them up and ask, many of the ISP's that DO firewall their customers don't tell them beforehand.
Check if you have any conflicting Firewalls that might be affecting or clashing with the router. If you have Windows XP, check out these instructions
on how to disable it.
Finally, there have been many issues covering this error message, so perhaps you'd like to run a Search
on it and see if any answers turn up. For best results, expand to 'All Forums' and 'All Posts'.
I hope you get it sorted soon