The least risk course of action is to follow the instructions in the manual (have it towed). But experience from many owners who post on this board and others like it indicates that there are several causes for these lights that do not interfere with driving to the dealer. Many of these conditions will actually clear (at least temporarily) and the lights will go off after a few off/on cycles. Unfortunately, if the lights go off, sometimes the computer error codes are also deleted, so your dealer won't be able to diagnose the problem.
So if you're not too risk averse, and your Prius still seems to drive normally, drive it to your dealer and ask them to read out the codes with as few power off cycles as possible. Otherwise, shut it off immediately and have it towed without turning it back on, to try to preserve the codes.
At 40K miles, the problem is probably still covered under warrantee. Good luck.
