It's just like Bug #5836, but with the "_name" - Array. If you have a couple of files to upload and the first is not set, then the array ${file."_name"} has only one key (index 0) with the name of the second (!) file. 
So when you loop through the file-array the wrong name is attached to the uploaded file.

Following function solves the problem:

function correctFileUploadBug($fp_sVarName) {

	GLOBAL ${$fp_sVarName}, ${$fp_sVarName."_name"};
	
	$aFile = &${$fp_sVarName};
	$aFileName = &${$fp_sVarName."_name"};
	
	$aNewFileName = Array();
	$j = 0;
	for ($i=0;$i<count($aFile);$i++) {
		
		if (trim($aFile[$i]) == "" || trim($aFile[$i]) == "none") {
			$aNewFileName[] = "";
			$j++;
		} else {
			$aNewFileName[] = $aFileName[$i-$j];
		}
	}
	unset($aFile);
	unset($aFileName);
	${$fp_sVarName."_name"} = $aNewFileName;
}