Have been getting similar message.
I set up my account in 1999, and this based dollar amounts as US.  
Have not been able to amend it to AUS$, and eBay helpdesk could not help to amend.  Their suggestion and only option.  Cancel my account and start again, or create a new Australian account.
If anyone has hints on how to ammed setting account to AUS$, it would be great to hear.