After porting a skybox from my favorite map, the ZIP file got corrupted as my computer just LOVES to do to all zip files I manage with Windows Explorer. God damnit, I forgot to put namecheck.txt and description.txt in using 7Zip. Anyways, most of the time my computer does this I just hide the ZIP and create another one with a different name to make up for it. But for Blockland it seems to be different, in that it looks at the addon and crashes due to a failure to open it up.
The console says this when the addon tries to get loaded:
Add-On is in the list of known bad add-on CRCs - will not execute
When I say a ZIP file is corrupted, this is what I mean: