Turns out it’s an environment issue. Many, many thanks to John, Dave and Jake for each following up and offering assistance. After an IM session with Jake (would that all tech support were so easy!), we determined that it’s our VPN software – apparently it’s configured to only allow access through IE. Should be a relatively easy fix.
Also, thanks to a number of you who followed up with offers of assistance, and to Matt Mower who spent a half hour with me (also by IM). Matt – congrats to the Giants!