When you install on the Pi it asks for username/password of your Weaved account so that we can register your device to that account. We don't create the account from the Pi installer.
When you first open your iOS app it also needs these credentials for connecting to your account. If you can see the device online then it seems as though the Pi side installed correctly.
So, beyond that, we have to ask what application are you trying to connect to on the Pi?
Please go through the steps in the post "What to do when it doesn't work":
This will give us some useful information to help get to the bottom of it.