PHP - Date_diff

I am trying to calculate the date and time difference between two timestamps.  I am using this for an auction style website and I thought it was working
fine until I woke up this morning and it said that there was only 1 hr left in auction when I actually started a 24 hour auction at like 7pm last night.

//trying to find date diff accurately
Code: [Select]
$now = mktime(date("g"), date("i"), date("s"), date("m")  , date("d"), date("Y"));
$end = $timestamp;
$start = new DateTime();
$start -> setTimestamp($end);

$current = new DateTime();
$current -> setTimestamp($now);

$interval = date_diff($current, $start, true);

$days = $interval ->format('%d');
$hours = $interval ->format('%h');
$minutes = $interval ->format('%i');
$seconds = $interval ->format('%s');

This is how I created the timestamp to store in the database for auction.
Code: [Select]
//Creates timestamp for when auction ends using auction
//length chosen.
$timestamp  = mktime(date("g"), date("i"), date("s"), date("m")  , date("d")+$auction, date("Y"));

Hi, so I am trying to get how many minutes and seconds are left from the datetime entry in the database and the current datetime, but I'm having issues...

Here's my code:
Code: [Select]
$query = "SELECT RequestMadeDateTime FROM TempAwaitingClients WHERE PSOID = '2'";
$result = mysql_query($query);
$row = mysql_fetch_assoc($result);
$RequestMadeDateTime = $row['RequestMadeDateTime'];
$currentDateTime = date('Y-m-d H:i:s');
echo 'Request Made Date Time: ' . $RequestMadeDateTime . '<br />';
echo 'Current Date Time: ' . $currentDateTime . '<br />';
echo date_diff($RequestMadeDateTime, $currentDateTime);

What I'm getting those is this, "Warning: date_diff() expects parameter 1 to be DateTime" ... Which I don't get because both variables are DateTime...

What this parameter 'absolute' in DateTime::diff does? I have done some tests but i cant percept what is different when i set this parameter 'true'.

Can you explain to me?!

Thanks a lot.

Best regards.