Thanks Andy,
I have alrady installed Microsoft Visual C++ 2005 SP1 Redistributable Package (x86) some days ago, so can be it has notthing to do with the channel change problem. It's my supposition...
I think something better for your success can be related to this BugFix:
Indeed the MS update doesn't have anything to do with the channel change (or any other tv related issue). It's only affecting the instlal process (DVB subtitle filter to be more specific).
Italy