minor tweaks
diff --git a/progs/tests/bufferobj.c b/progs/tests/bufferobj.c
index bbfa38a..93e3f8b 100644
--- a/progs/tests/bufferobj.c
+++ b/progs/tests/bufferobj.c
@@ -36,7 +36,7 @@
 {
    GLenum err = glGetError();
    if (err) {
-      printf("GL Error %d at line %d\n", (int) err, line);
+      printf("GL Error 0x%x at line %d\n", (int) err, line);
    }
 }
 
@@ -179,7 +179,9 @@
    for (i = 0; i < 500; i++)
       buffer[i] = i & 0xff;
 
+   obj->BufferID = 0;
    glGenBuffersARB(1, &obj->BufferID);
+   assert(obj->BufferID != 0);
    glBindBufferARB(GL_ARRAY_BUFFER_ARB, obj->BufferID);
    glBufferDataARB(GL_ARRAY_BUFFER_ARB, 500, buffer, GL_STATIC_DRAW_ARB);