What exactly are you trying to acomplish here ?
To put a donate button on a website that generates a brand new address on demand for everyone who wants to donate, so all the donors don't donate to a common address that can tie everyone together.
Call getaccountaddress "charity_name" when you generate the web page. You'll get the same address over and over, until somebody donates. Then you'll get a new address.
Then periodically call:
... and if the balance is greater than zero, call:
sendfrom "charity_name" charity_real_bitcoin_address amount
... to send the charity the accumulated coins.
If you deal with several charities this way, AND you're bundling up several donations before forwarding the coins to the charity, then it'll be hard to connect donors to particular charities.