Support is probably the best option as the hang can be due to that target file being corrupt or infected, but you could decide to exclude that entire folder - \windows\software distribution - from being scanned. Open OneCare, click Change settings, virus and spyware tab, Exclusion button, add that location (and any others you desire) to the exclusion list and it will not be scanned. If it contains an infection and you attempt to open or execute one of these files, OneCare's real-time protection should catch it.
-steve