The Official SBS Blog : RWW Error on Vista Clients:
Check out Wayne McIntyre and Justin Crosby’s post on RWW.
Quite frankly it’s rare to never that I enable that. I want to leave all data on the server anyway so that button is not checked. Plus it does add a but of complexity of migrating the data back to the server. Try ‘not’ to have to use that setting.
You’ll find most often than not you are fine without it enabled..