Why is she not responding to me?

met a very nice girl at a party one night, struck up a conversation got her phone number w/ the idea of making plans at a later date. we've been in touch since then and hung out last week. she came out w/ me and two married couple friends of mine. we had a very nice time, i spent most of the time talking to her, and as planned i walked her home after dinner. she was smiling and laughing the whole way home and when i dropped her off i mentioned that i really enjoyed spending time w/ her and looked forward to continuing that in the future. said good night (probably should have kissed her) and told her i'd speak to her the next day. long story short she hasn't responded to any of my contacts in the past week and a half. have no idea why! please shed some light and a course of action to re-establish contact...