Hi David,
Unfortunately CPS has to have a Continuous Protection Agent on every aspect of the remote server, this includes a business server that is being protected as well as the destination. This means the destination has to be Windows 2003 SP1 at a minimum. If the NAS box does not meet that requirement, then it will not work.
Please let us know if this helps to answer your question, and let us know if you have any other questions regarding this.
Thanks.
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