Anyone else seen system names showing as N/A, am aware of a similar issue where logged in user show as N/A. I'm using the plagued agent 18.104.22.16820, viruscan 22.214.171.1245 on epo 5.1.1.
Please make sure that on client machine, all the product are compatible as per KB82101.
VSE version 126.96.36.1991 looks from patch2 (don't remember exactly). With MA 5.0, supported patch for VSE is patch4. Please cross check other running products also on the client machine about compatibility.