It doesn't matter that Paypal will have to communicate with her in German. She's filed a complaint already, so clearly they are capable of doing so and are doing so already, that's their issue, not yours. Plus, she read and bid on your auction (which I'm guessing was in English), so her communication is likely better than she's letting on.
Contact Paypal and inform them that she's asking you to commit fraud, you have the emails to prove it and you want to cancel the sale and refund her money. The reason they are holding the money is so that they CAN refund it if you can't prove she's gotten the item, which you can't, because you haven't mailed it yet. Once you agree to the refund, they'll send her the money back and you're done with her. Like someone else said, if she gives you a negative, respond with the suggestion from above, but you might have to shorten it a bit to get it to fit: Buyer filed w/Paypal before item even shipped. Refunded to protect myself.
Get ahold of Paypal today and get this claim settled so you are free to sell it to the next person in line while they are still interested.
I have this number for Paypal in my records from a previous situation I had, hopefully it's still a working number. Say 'agent' to get a real person, 1-888-221-1161. Good luck!