my (
@explain,   @allanswers,     @allquestions,  $fullname,
$anslength, @allselections,  $file,          $fname,
$lname,     $time,           $reviewtime,    $idinput,
$id,        $courselocation, $useripaddress, $questionno,
@log,       $clocktime,      $log,           $type,
$value,     @answers,        $buttonname,    %selections,
@options,    $nds
);
[download]

I stopped reading here. This is almost always a warning that bad code follows. Saves me time that way.

You might want to look at reducing the number of global variables in your program, and especially want to look into documenting your variables as you introduce them.