ExifTool Forum

Hi all.
I made a simple cgi-script which lists the names of writable tags of JPG file. When I run it from the terminal ("$ perl test.pl" ), it returns the tag names like :

NewXMPxxxStructX
NewXMPxxxStructY
NewXMPxxxTag1
NewXMPxxxTag2
NewXMPxxxTag3

But when I open it from the web-browser, it shows nothing.
What is different between them?
The code is like below.

codes start-------
#!/usr/bin/perl -w

BEGIN { unshift @INC, "/usr/bin/lib" }
use Image::ExifTool qw{:Public};

print "Content-type: text/plain\n";
print "\n";

my @tags = Image::ExifTool::GetWritableTags("XMP-xxx");
for my $tag (sort @tags) {
   print $tag."\n";
}

-------codes end

Any help would be appreciated. Taka