"no last-modified header" when I try to use webdav with keeweb 1.6.1

How much time must pass to fix this error?
Fix it already. Most of the apps that are offered are very buggy and i could say not working.
Or take them out from your list and publish them when they at least work or fix them.
At least the keeweb people did a search for the problems source. And its your problem. Fix it.