*Can't Resolve Hostname*!!! Problem...

So, my friend just opened a Bukkit server with a hosting site called ServerMiner.com
The problem is that my other friends can join, but I can't. They also tried to join with their account from my computer, and it didn't work! So now I'm trying to solve the problem.
*I also tried to put the IP in numbers that I got from CommandPrompt, but that one says *Can't Reach The Server*.
*I also triple checked if the IP was right and it is.

I couldn't find the solution in other threads...