The only time I've had a similar problem is when my computer was not connected to the Internet.
The only other thing I can think of is how you've paid for Pirate101. If monthly or yearly, could your time have run out? Although, I think that you would still be able to access the free areas of the game.
Try restarting your computer and then, before anything else, try logging into Pirate101 after making sure you are connected to your internet.
Another thought is to uninstall Pirate101 using the Control Panel, restart your computer and re-install Pirate101.
If those don't work, use the Help Menu above (the Orange Question Mark) to contact Support. I'm sure that they will be able to help you. It can take them up to a day or two to get back to you.