EASIEST SOLUTION FOR YOU
1. Go into control panel
2. Select Uninstall a program
3. Look for Blockland
4. Click Uninstall
5. After uninstalling navigate here C:\Program Files (x86)
6. Delete the folder "blockland"
7. Download the latest version of Blockland and install it
(If that did not work then it is something to do with your video card)