I filled out the survey and Google Docs politely let me know that I couldn't submit it at the end.
If this is Google's problem, then I'm just writing this to let you know you are missing out on a lot of people filling out your survey because their stuff is broken. If this is you then hopefully you'll be able to do something about it.
I'm using Google Chrome 17.0.963.56 m.
Also your survey asks about average numbers of things over a given amount of time but the possible answers to those questions don't cover the 0-1 case, only 0, 1-2, etc..