I wasn't aware that Cakewalk included demo versions of PG and Sony plugins with Home Studio 2XL.
Did you install them off of the HS installation disk?
If you did, did they say DEMO or EVALUATION VERSION on them when you installed them?
If they were installed as either of the above, did you buy and register them yet?
The HS plugin patch only related to Cakewalk's own plugins right?
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There's No Big Mystery Here...
It seems to me that you probably have had demo versions of PG Power Tracks and a Sony product (Acid, Sound Forge, Vegas) installed on your computer at some point, and that the demo version of those plugins that installed with them are still listed in your computer's registry, and therefore showing up in HS's plugin list, but they were demo versions, and the time has expired. If you want those plugins to work, you would have to buy the programs that they came with.