I haven't been able to use TV System Update on my T43 for sometime now. After downloading ca. 20% (but it varies) of package information, it halts with "Error 77 received from the Package Index Server. Please contact the Support Center."
I have manually downloaded and installed version 313-2008-3-13. As part of installation, it looked like it uninstalled the previous version and removed the settings. Despite this, I still get the same error.
I have same issue. I bought a T60P with XP pro a year ago. I have since installed Vista Business and also a virtual pc with XP pro and with Vista as host. I have XP pro (virtual) setup on my home network. I am wireless (with printer wireless) and all works well. I am running NOD32 and Outpost Firewall Pro on virtual (2007). When I installed ThinkVantage System Update all went well till I got same message as you did. ThinkVantage System Update works ok with host, which is Vista, but not on virtual.