I've actually already tried what you reccommended: reinstalling the app. It's weird though, I have two accounts and the one with more contacts in it loads up just fine. It's the one with the smaller number that doesn't seem to work.
i have the same problem on my 3g Vita. Haven't tried to use it with wifi. I hope at some point someone can work it out. I signed up for calling but having no contacts means i can't send messages or skype to skype.
I can't for the life of me figure out why so few people would be having this problem.... Is there some place i might be able to get some sort of support? I understand its a free app but i am a paying customer, and as is the app is basically just a phone with no phonebook.