The VDL2 Kontakt Player is 8-part multi-timbral, meaning it's capable of playing back 8 separate midi channels in each instance of the player. While this suits many users just fine, you may wish to play back more than 8 tracks in your scores. If this is the case, you have a few options.
1) Host multiple instances of the VDL:2 player by using it as a plug-in in a VST or AU "host" program. By loading multiple instances of VDL:2 into a host program, you can then save the session so when you re-launch it, all your settings will be intact. There is a discussion topic about various host programs on the Tapspace Forum here.
2) Purchase the update to VDL 2.5 which integrates into a completely redesigne Kontakt Player by Native Instruments. Newer versions of Kontakt Player allow 64-part multi-timbrality in standalone mode or 16 channels per instance if you're using it as a plug-in. Registered VDL:2 user may purchase an update to VDL 2.5 for $69. VDL:2 (and its older version of Kontakt Player) is no longer available.