diff -r bbf46f59e123 -r 25ffed67c7ef m3g/m3gcore11/src/m3g_vertexbuffer.c
--- a/m3g/m3gcore11/src/m3g_vertexbuffer.c	Tue Aug 31 16:31:06 2010 +0300
+++ b/m3g/m3gcore11/src/m3g_vertexbuffer.c	Wed Sep 01 12:39:21 2010 +0100
@@ -350,7 +350,8 @@
     if (newArray != NULL) {
     	if (buffer->arrayCount == 0 || (buffer->arrayCount == 1
                                         && change == 0)) {
-    		buffer->vertexCount = m3gGetArrayVertexCount(newArray);
+    		buffer->vertexCount =
+                (newArray != NULL ? m3gGetArrayVertexCount(newArray) : 0);
     	}
     	else if (m3gGetArrayVertexCount(newArray) != buffer->vertexCount) {
             m3gRaiseError(M3G_INTERFACE(buffer), M3G_INVALID_VALUE);