Why can't I autotune to my songs from my iPhone library?

I am having troubles trying to autotune to my own songs in
my iPhone library. Everytime I pick a song it starts the count-in and
plays the song in the app, but it sounds like my mic is turned off by
the app and nothing records. After saving, it also is all of the parts
of the song I have recorded, minus what should have been my mic's
input, but it is all contained in one second on the play bar.
I don't know why it would do this, because my iPhone and it's mic
works fine with all the other autotune tracks on this app. I also
don't understand why this app would have the option of using
songs from my iPhone's library if those songs didn't work.

Please answer! Thank you!

Try turning phone off & on, and re opening the application.
I've recorded many many songs to my own libary tunes, and nothing like this has ever happened, very strange!

The exact thing is happening to my phone, I don't know how to fix it.

If anyone is running iPhone OS 3.0 or 3.0.1, then its an Os bug. Updating the OS to 3.1 or newer will fix this.

elon