Warning message: Number format……..

Hi
I got this message, not found answer from other topics.

Warning: number_format() expects parameter 2 to be long, string given in C:\WAMP\www\autostopp\wp-includes\functions.php on line 143

and line 143 is here:
$num = number_format( $number, $decimals, $wp_locale->number_format[‘decimal_point’], $wp_locale->number_format[‘thousands_sep’] );

Sorry, if too noob Q ??