But the Webmaster Tools do not say robots.txt is invalid. It says it ignored one line. I suppose ignoring something does not normally means it totally rejects the whole file, and therefore cannot crawl because it doesn't know if robots.txt allows it to crawl? That wouldn't make sense.
The key issue I think still is "what does zero percent mean? success or failure?".
So far nobody seems to know. But hey, it's Sunday and Easter, so I shouldn't be so impatient.