If WinTV 10 can receive the "W" channel, that rules out my previous suggestion of a weak MUX with marginal signal strength.
My best guess at the moment would be a corrupted channel database...
We all waste far too much of our lives trying to get software to work, so if you have now found a software solution that does what you want, you should continue using it. (y)
If it turns out that...
Looking at recent activity on the web site, it has been 4 weeks since any of the MP2 developers have been active. They may be taking a short (or an extended) break. For this reason I would suggest...
My recommendation would be to upgrade your TV Server system and all of your client systems to MP 1.33.
There is always scope for things to go wrong (especially if upgrading from 1.12 to 1.33 --...