library: http://wiki.github.com/masterexploder/PHPThumb/basic-usage

i am using the PhpThumbFactory library to crop and upload an image. the error im receiving is this:

Fatal error: Uncaught exception 'Exception' with message 'Image file not found: ' in /www/iaddesign/admin/classes/phpthumb/ThumbBase.inc.php:193 Stack trace: #0 /www/iaddesign/admin/classes/phpthumb/ThumbBase.inc.php(172): ThumbBase->triggerError('Image file not ...') #1 /www/iaddesign/admin/classes/phpthumb/ThumbBase.inc.php(110): ThumbBase->fileExistsAndReadable() #2 /www/iaddesign/admin/classes/phpthumb/GdThumb.inc.php(96): ThumbBase->_construct('', false) #3 /www/iaddesign/admin/classes/phpthumb/ThumbLib.inc.php(127): GdThumb->_construct('', Array, false) #4 /www/iaddesign/admin/portfolio.php(29): PhpThumbFactory::create('') #5 {main} thrown in /www/iaddesign/admin/classes/phpthumb/ThumbBase.inc.php on line 193

here is the snippet that is for the image to be uploaded.

/* -------------------------------------------------------------------- */
/*                        SAVE ICONS                                    */
/* -------------------------------------------------------------------- */



$icononsrc = $_FILES['iconoff']['tmp_name'];
$iconoffsrc = $_FILES['iconon']['tmp_name'];

$thumboff = PhpThumbFactory::create($iconoffsrc);
$thumbon = PhpThumbFactory::create($icononsrc);



$thumboff->adaptiveResize(200,151);
$thumbon->adaptiveResize(200,151);

$thumboffname = "uploads/".$_FILES['iconoff']['name'];
$thumbonname = "uploads/".$_FILES['iconon']['name'];

$thumboff->save($thumboffname, 'jpg');
$thumbon->save($thumbonname, 'jpg');