Note to carry this on further than it needs to be, but that's like writing this code:

void call_me(char *str,char *str2)
{
fprintf(stdout,"%s\n",str);
//str2 not referenced
}

void...

Yes, that's what it was.

So, for anybody else that searches and stumbles onto this:

For only nVidia PC drivers (not OS X), if you enable a vertex array that doesn't exist in the shader, it'll...

It's an access violation.

As always, the minute I post this, I think I've found the problem, but will need to verify with my users, hopefully by tomorrow. It has to do with...

I'm the author of an open source, cross-platform freeware 3D engine dim3 (www.klinksoftware.com). Two components: the engine and the editor. The editor is all fixed function, it works everywhere. ...