When i try to create an instrument, such as marimba rosewood birch, it tells me that i have (number) files missing. I've done numerous installs of the library, and I've made sure that everything is located where it should be. Please help I'm so lost.

Most likely your sample files (the three .nkx files located in your Virtual Drumline 2.5 folder) have been moved, or are in a location other than that which KP2 is looking for them. You can either move the files to the location listed in KP2, or reset KP2 to locate them at their current location. There's a topic about this here:

https://www.tapspace.com/forums/index.php?topic=2036.0