Aside from the extreme ambiguity of "cannot add image to library:0" error we all know of, here's a couple more:
"Weapon does 0 damage" - this will be especially annoying in 1.0, once we have damage-less weapons firing debuffs around. There should be something we can put into the weapon's data field that will over-ride this message.
"content expected" error when it should be "closing tag does not match opening tag" - mostly due to the confusion it can cause: http://xelerus.de/index.php?s=mod&id=362#1576 - I've seen this same error-swap in my own mod occasionally. Transcendence should check to see why there was no content, to see if it was actually caused by a more specific error, since most people interpret "content expected" as missing data, rather than a missing closing tag.
