Some nice situations can jump at your face when playing around with install/upgradepkg and "failing" with them in some way. For example I accidentally installpkg'd a package that I actually should have upgradepkg'd, and as a result had two different versions of the same package installed. Ok, it worked, but pkgtool showed me the two different versions, and refused to remove the older one (that got overwritten, but package name still left behind). Solution was to remove both versions of the package (run removepkg on the package twice in a row), and then installpkg the newer version again..trickier than one might think. Especially if you thought that installpkg on a package that is already installed would cause upgradepkg actions..no
So try installpkg if it works, and if not, you can always removepkg = make sure the package is completely removed, and then install it again.