diff --git a/php4/rrdtool.c b/php4/rrdtool.c
index 451fddb..4a3a69c 100644
--- a/php4/rrdtool.c
+++ b/php4/rrdtool.c
@@ -373,7 +373,7 @@ PHP_FUNCTION(rrd_update)
argv[3] = estrdup(opt->value.str.val);
optind = 0; opterr = 0;
- if ( rrd_update(3, &argv[1]) != -1 )
+ if ( rrd_update(2, &argv[2]) != -1 )
{
RETVAL_TRUE;
}