Hey frogboy,
I might be able to help.
First of all: this is the correct youth hostel
http://www.jugendherberge.de/en/youth-h ... 2/Portrait
Here you find the email and the phone number (if you decide to call, make sure to dial
49 (for Germany)
211 (for Düsseldorf - drop the 0, for that's only within Germany) then the phone number
557...)
What I did today, I called them referred to the booking number you schould have received by Dr. Luis LaVeel and they put in the booking. Since it is a big youth hostel with lots of international guests I am very confident they speak english over there. So you should be able to call or write them an email without any worries.
If that should not succeed, write me a PM and I check if I can do anything. Apart from that, Dr. Luis LaVeel probably has a direct connection to them as well...