In spite of the very frequent updates recommended for Microsoft Vista, there's a bit a saving grace in that they generally don't require a restart.  However, there may have been an issue with FTP tied to this most recent update.  The update was completed on 05/21/2009 but unfortunately, no note of which update was made.  Regardless, a short time later there seemed to be a system-wide failure to connect to FTP sites via domain name.  NOTE:  There was however success connecting with IP addresses.

It's not immediately clear what, if any, connection between FTP and this recent Vista update there may be.  In any case, a restart of the system corrected the issue.  As a matter of practice, regardless of whether or not the update indicates that a restart is required it may be a good idea to perform one after each update.