diff -u -r a/src/glx/x11/glxcmds.c b/src/glx/x11/glxcmds.c
--- a/src/glx/x11/glxcmds.c	2009-06-26 14:15:34.000000000 -0400
+++ b/src/glx/x11/glxcmds.c	2009-06-29 19:06:33.043742661 -0400
@@ -164,7 +164,7 @@
 {
     __GLXdisplayPrivate * const priv = __glXInitialize(dpy);
 
-    return (priv->screenConfigs != NULL) ? &priv->screenConfigs[scrn] : NULL;
+    return (priv != NULL && priv->screenConfigs != NULL) ? &priv->screenConfigs[scrn] : NULL;
 }