This sounds like it is related to your drivers, if you have a newer motherboard made by Nvidia, you may have their ActiveArmor firewall software, as it comes with nForce chipset drivers. This program can be a major hassle.
But I think that after the update, the firewall you are using (if you are using one) might not recognize Blockland 1.03 as the same program as Blockland 1.02. I would recommend that you backup any saves and try a fresh reinstall from here:
http://blockland.us/files/Blockland_1_03.exeThis is the newest official version, and should repair any errors.