I had the same problem. I found the following workaround: Use an old address from a transaction from the old wallet. You can find such addresses in the "History" tab of your wallet. This did the job for me. I'm not sure but I think with the old version XSH addresses started with "S". This seems not to be case for the wallet 3.0 anymore. I assume CE still has a check active, and refuses withdrawals with addresses not starting with "S". But this is pure speculation :-)