Jeff,
Check if running the ArcGIS File Handler -- C:\Program Files (x86)\Common Files\ArcGIS\bin\ArcGISFileHandler.exe, and toggle the Layer options from Automatically select to ArcGIS Explorer, or alternatively ArcMap, is of any help.
Similar for the Web Map Options panel--select ArcGIS Explorer or ArcMap as you need.
Also, it will apply to all ArcGIS component launches, but you might toggle the Package Location Options from Automatically Select to a user specified location (where you've write access and good access--definitely not a network share).
Post back if using the file handler GUI helps.
Stuart
