Combination patches are instrument files that link the different volumes together for a library. These patches are meant to be used if you own more than one volume of a product, e.g. Volumes 1-4 of our Chamber Strings (Sable) range.
If you only one volume, then these combination patches will not work.
The combination patches take the form of "Patch name (vol1+vol2+vol3+vol4)"
So if you have say Vols 1 + 2, you can use the combination patches that state they are for vol1+vol2.
If you try to load combination patches that include volumes that you do not own, you will get a 'Samples Missing' error message within Kontakt. This appears because you do no own the sample content and subsequently cannot load that combination patch.
There is more information on this available HERE