ARL dst idx was undefined.
diff --git a/src/mesa/shader/arbprogparse.c b/src/mesa/shader/arbprogparse.c
index a64360a..a3c433b 100644
--- a/src/mesa/shader/arbprogparse.c
+++ b/src/mesa/shader/arbprogparse.c
@@ -2296,7 +2296,8 @@
 {
    struct var_cache *dst;
    GLuint result;
-   (void) Index;
+
+   *Index = 0; /* XXX */
 
    dst = parse_string (inst, vc_head, Program, &result);
    Program->Position = parse_position (inst);