New Windows installation, same computer, XPproSP3. USB & network OK. Disabled A/V & firewall, scanned in device mgr scan, rebooted - ineffective. Never happened before. Update returns messages below.

Initializing
Getting information
Software version: 7.7.0
Hardware: Board 2.5.0 (0xFF:0x12)
Firmware: 2.6
Getting information - Successful
Checking version information - Successful
Waking remote - Successful
Getting remote states - Successful
Uploading remote information
Initializing remote
Uploading remote control information to web : The information updated to the web site is invalid. - The information was not sent. Check your USB cable and try again. If the problem persists, contact customer service.

Televison & Video - Logitech - Harmony 550 Remote Control