PHP Fatal error:  Cannot redeclare unixdate() in /web/htdocs/home/pnadodb/adodb.inc.php on line 147

Here it's the code that generate the error:
--------
        /**
         * Also in ADORecordSet.
         * @param $v is a date string in YYYY-MM-DD format
         *
         * @return date in unix timestamp format, or 0 if before TIMESTAMP_FIRST_YEAR, or false if invalid date format
         */
        function UnixDate($v)
        {
                if (!preg_match( "|^([0-9]{4})[-/\.]?([0-9]{1,2})[-/\.]?([0-9]{1,2})|",
                        ($v), $rr)) return false;

                if ($rr[1] <= TIMESTAMP_FIRST_YEAR) return 0;
                // h-m-s-MM-DD-YY
                return mktime(0,0,0,$rr[2],$rr[3],$rr[1]);
        }
----------------
The funcion is called in this way:
---
else $d = ADOConnection::UnixDate($d);
--------

The same program works find with Apache1.3.27+php-4.2.3 

You can try this program at http://php.weblogs.com/ADODB
it's named "ADOdb Library for PHP"

Regards.