I have directly asked a google engineer this question and no (exceptions are if it causes the spider to be redirected or unable to parse through the site) However, all errors are fixable and my experience is what you don't fix in stage one will become your worst headache in stage 5.... I always write code to validate.. it makes it lighter.. render in all engines correctly and helps people who have accessibility issues.. but that is me and I know I am stricter on myself than most..

so to answer your question no it won't have an affect, but do you want to put up invalid work?
Completely up to you which is most important..

Thanks!!