I asked about turn-over rates. You know that if a company has a high turnover rate, the job sucks ass.
As for weaknesses - I think you should mention something that you are simply inexperienced with, but can easily learn. For example, I told my current boss that I needed to improve my computer skills because I really only use it for email and reading the news. My hope was to convey that I wasn't afraid of computers, but simply hadn't really worked with them before.