2.3.1 problem with Leopard?
 

I can control our server (the music server is an old G3 still on Tiger) from Leopard via the menu bar and the buttons in the netTunes Servers list, but I can't get the GUI to come up. I get a white rectangle of approximately the right size. I'm using a G5/DP, but thesame thing happens from my wife's G4 laptop.

Is this a known/fixable issue?

As indicated on the netTunes page, netTunes is not currently compatible with Leopard due to a bug in Leopard itself. We're waiting for a fix...