For some reason when I use notehead 2 to indicate crossovers in the tenor parts, drums 1, 2, 3 all play back one drum higher but drum 4 is unaffected. 

Help!

Windows XP pro
Sibelius 4
VDL 2 with updated library

anyone???

If you're using mapped instruments/staff types in Sibelius (like the ones in the VDL templates), changing noteheads will generally affect how Sibelius plays back. I would recommend you indicate your crossovers in a different way.

Using the forum's search for ";crossovers"; yielded some good results. In particular, here's someone else who asked the same question you did:
https://www.tapspace.com/forums/index.php?topic=2096.0

There was also a productive and interesting conversation on this topic here:
https://www.tapspace.com/forums/index.php?topic=2096.0

Hope this helps.