The only thing I can think of is that either Blockland can't find the .blb files or they are corrupt.
These type of errors are usually with certain mods you have or just Windows acting up and being stupid. Remove all your mods, Just cut them out onto another folder on your desktop. If you see the crash goes away try and think of what mod you have that would make something with Bricks crash.
Press the ` key located to the left of the 1 key on standard keyboards while on your server, you will get a window type in "trace(1);" without quotes, press the ` again, plant a brick, and then post your console log