Had calls from two of our client's staff this morning who are working from home and connecting to an SBS 2003 server from their own PCs.

Both had had this month's security updates downloaded to their PC last night and could not connect to RWW this morning.

It turned out that we had to place the URL for their company's SBS box in Trusted Sites in IE. Why it wasn't already there and why it had worked before (they both were running SP3) is a mystery.