Threaded Texture Download Problem on NVidia

I have an application which uses a background thread to download texture. It uses wglShareLists() to share a rendering context between the background window and the foreground. The application works on multiple graphics cards, but I have noted some instability in the NVidia drivers (only on NVidia) whereby the textures are sometimes not bound or the wrong texture is bound. The problem seems to get worse over time. Does anyone have any idea how I can get around the problem, short of moving the download into the foreground loop? I have experimented with glTexSubImage and so on, and am able to get the download time to go quickly, but it is still a sub-optimal solution. One further note: the problem only crops up on a multi-processor machine.

[This message has been edited by MarkSnyder (edited 06-06-2001).]