I know this problem from my ThinkPad a long time ago. The solution at that time was to shut down the laptop (completely, not just sleep or something like that) and then remove the battery, wait 1 minute, insert it again and start. Somehow the laptop had saved something that only worked again after removing the battery.
Also there was the problem that not all power supplies on the dock worked. The dock should have its own power supply with more power. The normal laptop battery might be too weak.
