Unfortunately accented characters like äöü are completely different to aou from the computer's perspective.
The Export Path in particular will require modification if your project title includes German characters as it will only accept: [a-z] [A-Z] [0-9] "." "_":
abcdefghijklmnopqrstuvwxyz ABCDEFGHIJKLMNOPQRSTUVWXYZ 0123456789 . _
The name of your project automatically becomes the export path, even if the characters won't export (I think). So you'll need to modify that to be basic Latin only.
But the Package Name or "Name" can include other characters. This is the actual title of your app when it is in the app list. So your export path might be
/aou.apk but on the phone the app is titled