1.0.0.621: ModBuddy upload "Failed with code - UnknownError"

I'm trying to upload a new mod to the mod browser using ModBuddy. I select the package, it passes all the checks, so I advance to the next screen, where it fails to upload, reporting the message "Failed with code - UnknownError". See attached screenshot.

I tried this 3x in a row with the same results. Then waited half an hour, tried again, same problem. This is my first attempt to upload this particular mod. But I'm a fairly seasoned modder, and have uploaded 3 different mods previously without any issues using the account. I don't think there is anything wrong with the mod itself, as I've had people beta-testing it here for a week and this version doesn't change the functionality at all. I was able to load a game normally with this new mod version enabled.

I have no idea what to try and fix, since I have no clue as to why it's failing. Anybody else had this happen?

With Thalassicus' help, I was finally able to get my mod uploaded, but this is definitely a bug. It turns out that if your mod description is fairly close to the limit of 1024 characters, it can trigger this error. I had it happen at a length of 996. Then I cut it further, to 963, and it uploaded!

See http://forums.civfanatics.com/showpost.php?p=9928268&postcount=15 for a cheap way to save some description length by removing the useless control-return & line-feed characters.

Having exactly the same error, even though the description box is far far less than the character limit (Its about two sentences).

Tried everything I could possibly think of and it won't let me upload it. (Note, this is after the latest patch). The mod does run absolutely fine on my computer though, which makes this all the more annoying. I've attached the mod for anyone who wants to look through it. Its absolutely tiny and only includes 4 lines of SQL code.