Perl errors: "seek() on unopened filehandle", "readline() on unopened filehandle", and "XML::Mini Error MESSAGE:XML::Mini::Document::fromFile() Can't find file"

I usually have run my CGI script on Debian without problems. I tried to install it on a fresh install of Ubuntu, but receive this in the Apache 2 error.log:

[Fri May 17 13:06:09 2013] [client 192.168.1.108] seek() on unopened filehandle at /usr/lib/cgi-bin/NFS1.pl line 432.
[Fri May 17 13:06:09 2013] [client 192.168.1.108] readline() on unopened filehandle at /usr/lib/cgi-bin/NFS1.pl line 433.
[Fri May 17 13:06:09 2013] [client 192.168.1.108] Use of uninitialized value $input in pattern match (m//) at /usr/local/share/perl/5.14.2/XML/Mini/Document.pm line 271.
[Fri May 17 13:06:09 2013] [client 192.168.1.108] Use of uninitialized value $filename in -e at /usr/local/share/perl/5.14.2/XML/Mini/Document.pm line 246.
[Fri May 17 13:06:09 2013] [client 192.168.1.108] Use of uninitialized value $filename in concatenation (.) or string at /usr/local/share/perl/5.14.2/XML/Mini/Document.pm line 246.
[Fri May 17 13:06:09 2013] [client 192.168.1.108] XML::Mini Error MESSAGE:XML::Mini::Document::fromFile() Can't find file
[Fri May 17 13:06:09 2013] [client 192.168.1.108] [Fri May 17 13:06:09 2013] NFS1.pl: XML::Mini Error MESSAGE:XML::Mini::Document::fromFile() Can't find file
[Fri May 17 13:06:10 2013] [client 192.168.1.108] File does not exist: /var/www/favicon.icon

The browser gives this output:
Software error: XML::Mini Error MESSAGE:XML::Mini::Document::fromFile() Can't find file

Here are the code blocks that the error code refers to in my script:
seek() on unopened filehandle at /usr/lib/cgi-bin/NFS1.pl line 432
readline() on unopened filehandle at /usr/lib/cgi-bin/NFS1.pl line 433.

These lines are lines 31 and 32 below:

sub getMovieInfo {
	my $movieName = shift;
	my $processedMovieName = nameProcessor($movieName);
	my $searching = 1;
	my ($imageLink, $rating, $genre, $imdburl, $plot, $year);
	#This loop will run maximum twice. Again if the moviename ends in a four digit number and we didn't find anything the first time.
	#The second time it runs it will be without the four digit number at the end of the movie name.
	while($searching) {
		my $xmlDoc = XML::Mini::Document->new();
		#1. Thus URL will give us an XML document to parse:
		my $url = "http://imdbapi.org/?title=".uri_escape($processedMovieName)."&type=xml&plot=simple&episode=1&limit=1&yg=0&mt=none&lang=en-US&offset=&aka=simple&release=simple&business=0&tech=0";
		#print "<b>".$processedMovieName."</b> - Trying: <font size=\"-1\">" . $url . "</font><br>";
		#2. Download the url and extract the information(imageLink/cover: OK, genre: OK, rating: OK):
		my $xml;
		$genre = " ";
		#print "Called getMovieInfo() for " . $movieName . "<br> - " . $processedMovieName . "<br> - ".removeNoiseWords(lc($movieName))."<br><br>";
		if($url =~ /http/) {
			#print "   URL OK!<br>";
			my $response_body = tempfile();
			my $curl = WWW::Curl::Easy->new;

			$curl->setopt(CURLOPT_HEADER, 1);
			$curl->setopt(CURLOPT_URL, $url);
			$curl->setopt(CURLOPT_WRITEDATA, \$response_body);

			my $return_code = $curl->perform;
		
			my $getNextLine = 0;
			if ($return_code == 0) {
				my $response_code = $curl->getinfo(CURLINFO_HTTP_CODE);
				seek($response_body, 0, SEEK_SET);     # reset filehandle to beginning of file
				while (<$response_body>) {
					$xml .= $_;
				}
				$xmlDoc->parse($xml);
				my $xmlHash = $xmlDoc->toHash();
				$rating = $xmlHash->{'IMDBDocumentList'}->{'item'}->{'rating'};
				if(ref $xmlHash->{'IMDBDocumentList'}->{'item'}->{'genres'}->{'item'} eq 'ARRAY') {
					foreach my $genreElement (@{$xmlHash->{'IMDBDocumentList'}->{'item'}->{'genres'}->{'item'}}) {
						$genre .= $genreElement . " ";
					}
				} else {
					$genre .= $xmlHash->{'IMDBDocumentList'}->{'item'}->{'genres'}->{'item'} if(exists($xmlHash->{'IMDBDocumentList'}->{'item'}->{'genres'}->{'item'}));
				}
				if(ref $xmlHash->{'IMDBDocumentList'}->{'item'}->{'poster'} eq 'ARRAY') {
					foreach my $imageLinkElement (@{$xmlHash->{'IMDBDocumentList'}->{'item'}->{'poster'}}) {
						$imageLink .= $imageLinkElement . " ";
					}
				} else {
					$imageLink = $xmlHash->{'IMDBDocumentList'}->{'item'}->{'poster'};
				}
				$imdburl = $xmlHash->{'IMDBDocumentList'}->{'item'}->{'imdb_url'};
				$plot = $xmlHash->{'IMDBDocumentList'}->{'item'}->{'plot_simple'};
				$year = $xmlHash->{'IMDBDocumentList'}->{'item'}->{'year'};
			} elsif($return_code == 56) {
				#If the return code is 56, then we have been interrupted. We loop and try again.
				$searching = 1;
				next;
			} else {
				print ("An error occured: ".$return_code." ".$curl->strerror($return_code)." ".$curl->errbuf." at initiateMovieInfo() when treating ". $url ."\n");
			}
			#print "   -->" . $rating . " " . $imageLink . " " . $genre . "<br>";
		}
		if(defined($rating)) {undef($rating) if($rating eq "");}
		if($processedMovieName !~ m/\b\d{4}\b$/){$searching = 0;}
		if($processedMovieName =~ m/\b\d{4}\b$/ && !defined($rating)){$processedMovieName =~ s/\b\d{4}\b$//;}
	}
	$imageLink =~ s/\s+$// if(defined($imageLink)); #remove trailing spaces
	if(defined($genre)) { $genre =~ s/\s+$//; $genre =~ s/^\s+//;} #remove trailing spaces #remove leading spaces
	#print "   Returning -->" . $rating . " " . $imageLink . " " . $genre . "<br>";
	my @infoArray = ($imageLink, $genre, $rating, $imdburl, $plot, $year);
	return \@infoArray;
}

All help is very much appreciated.