reset error state before parsing (David Reveman)
diff --git a/src/mesa/shader/arbprogparse.c b/src/mesa/shader/arbprogparse.c
index 9d78027..5b5924c 100644
--- a/src/mesa/shader/arbprogparse.c
+++ b/src/mesa/shader/arbprogparse.c
@@ -3762,6 +3762,9 @@
    GLubyte *strz = NULL;
    static int arbprogram_syn_is_ok = 0;		/* XXX temporary */
 
+   /* Reset error state */
+   _mesa_set_program_error(ctx, -1, NULL);
+
 #if DEBUG_PARSING
    fprintf (stderr, "Loading grammar text!\n");
 #endif