You typically want to pitch the starter, when it is still active (bubbly). After the yeast have consumed most of the sugars in your starter they take a siesta on the bottom. You can boil/cool some more wort and feed them again, to get them going. If they were at room temp 60-75, they were probably fine. If it was too hot 75º+ for too long, they may have died off. You will also want to try to "match" the temp of your starter with the wort you are pitching into. Pitching a 75º starter into a 65º wort can stun them a bit. Odds are, though, your yeast were fine, they may just need 24 hours to get rolling.