1. Update video drivers
http://blockland.us/driverupdate/2. If it still doesn't work, post the contents of your console.log file so we can see what's wrong.
* Run the game and have it crash/fail
* Exit game if necessary
* Right click your Blockland Shortcut
* Click "Properties"
* Click the "Find Target" button ("Open File Location" in Vista)
* This will open your Blockland folder, in this folder there is a file called console.log (it may appear as just "console")
* Either post this file as an attachment or open the file in notepad and copy all of the text into your post.