I'm an Australian living in Austria.I'm flying home via Düsseldorf and Hong Kong but my Passport is only valid for about a Month. I'm only staying at each Airport for about an hour so i'm wondering if i will have any problems because my passport is only valid for a nother month. Hope someone can help me Cheers!
You should be OK. As an Australian citizen, you have an unconditional right to enter Australia, and your travel document (passport) will still be valid when you show it to the airline at check-in.
Schengen exit immigration in Düsseldorf will not stop you from leaving, and you will not go through immigration at all in Hong Kong. (Note: I'm assuming your flights are booked on the same ticket, which I hope is the case if you only have an hour to transfer.)