PHP Error only present in Internet Explorer - php

Question

Okay this has baffled me. My script works in Mozilla but not IE. I get this error in IE:
Warning: move_uploaded_file(uploads/properties/yh96gapdna8amyhhmgcniskcvk9p0u37/) [function.move-uploaded-file]: failed to open stream: Is a directory in /homepages/19/d375499187/htdocs/sitename/include/session.php on line 602
Warning: move_uploaded_file() [function.move-uploaded-file]: Unable to move '/tmp/phpJkiaF3' to 'uploads/properties/yh96gapdna8amyhhmgcniskcvk9p0u37/' in /homepages/19/d375499187/htdocs/sitename/include/session.php on line 602
my code at Session.php is:
function addPhoto($subphotoSize,$subphotoType,$subphotoTmpname,$subphotoDesc,$subfieldID,$subsessionid){
global $database, $form;
/* Get random string for directory name */
$randNum = $this->generateRandStr(10);
$maxFileSize = 2500000; // bytes (2 MB)
$filerootpath = PHOTOS_DIR.$subsessionid."/";
if($subphotoType == "image/png"){
$filename = $randNum.".png";
} else if ($subphotoType == "image/jpeg"){
$filename = $randNum.".jpg";
}
$fullURL = $filerootpath.$filename;
/* Image error checking */
$field = "photo";
if(!$subphotoTmpname){
$form->setError($field, "* No file selected");
} else {
if($subphotoSize > $maxFileSize) {
$form->setError($field, "* Your photo is above the maximum of ".$maxFileSize."Kb");
} else if (!is_dir($filerootpath)){
mkdir($filerootpath,0777);
chmod($filerootpath,0777);
}
move_uploaded_file($subphotoTmpname, "$fullURL");
}
/* Errors exist, have user correct them */
if($form->num_errors > 0){
return 1; //Errors with form
} else {
if($subfieldID == "1"){ // If the first field...
$is_main_photo = 1;
} else {
$is_main_photo = 0;
}
if(!$database->addNewPhoto($ownerID,$subphotoDesc,$fullURL,$userSession,$is_main_photo, $subsessionid)){
return 2; // Failed to add to database
}
}
return 0; // Success
}
It creates the folder no problem but doesnt do anything else.

Answer 1

Add a log message to see what's the value of $subphotoType. My guess is that when you upload the file from Internet Explorer it's neither image/png nor image/jpeg, in which case $filename will be empty because you don't have an else clause.
if($subphotoType == "image/png"){
$filename = $randNum.".png";
} else if ($subphotoType == "image/jpeg"){
$filename = $randNum.".jpg";
} else {
// No else! $filename will be empty.
}
If you tune your error reporting settings properly you should see a notice saying you are trying to use an undefined variable.