Make sure you're running as an administrator. If you're not sure how to check, follow these instructions:
1. Start Menu
2. Control Panel
3. Users/User Accounts
4. What does it say under your name?
Also, turn off your firewalls and antivirus just to check if those are the issue. If turning them off allows LC to run, then you'll need to find how to add to the exceptions on the firewall or antivirus and add LC.exe and Nksp.exe. For more information on firewalls/antivirus, check here:
Then, check your connection:
1. Run the test at http://www.bandwidthplace.com/
and post your results here.
2. Go to your Start Menu ---> Click on "Run" (For Vista users, this will be under "All Programs" ---> "Accessories") ---> Type in "cmd" and hit click "Ok" ---> Type in "ping www.aeriagames.com"
---> Post the results under "Approximate Time" here.
If all this fails, you'll need to uninstall, delete the game folder, download the installer, and reinstall.
If you're freezing up during patching (Not the Cannot Connect to Server error), then try the manual patches (The manual patches are UNofficial and are not sanctioned by Aeria Games. There have been issues with people who used it in the past. So use at your own risk!