It doesn't sound right the script got displayed instead of browser asking you to download it. Because if they browser is not receiving a text/html or text/plain http header, it probably shouldn't display the file (for security reason). You could check your Apache's httpd.conf file to see (if CGI) whether you have something like:

<IfModule mod_alias.c>

    # .... other stuff .....

    ScriptAlias /cgi-bin/ "d:/apache/cgi-bin/"
    <Directory "c:/apache/cgi-bin/">
        AllowOverride None
        Options None
        Order allow,deny
        Allow from all
    </Directory>

    # .... other stuff .....

</IfModule>
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If mod_perl, it could be:

# ... other stuff ....

LoadModule perl_module modules/mod_perl.so

# ... other stuff ....

<IfModule mod_alias.c>

    # ... other stuff ....

    Alias /mod_perl/  "c:/apache/mod_perl/"
    # s.t. http://host/mod_perl/script.pl
    <Location /mod_perl>
        AllowOverride None
         SetHandler  perl-script
         PerlHandler Apache::Registry
         Options +ExecCGI
         PerlSendHeader On
        Order allow,deny
        Allow from all
    </Location>

    # ... other stuff ....    

</IfModule>
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or

# ... other stuff ....

LoadModule perl_module modules/mod_perl.so

# ... other stuff ....

PerlModule Apache::DBI Apache::Request 

# ... other stuff ....

<Files ~ "\.pl$">
    SetHandler perl-script
     PerlHandler Apache::Registry
     Options ExecCGI
    PerlSendHeader On
    PerlInitHandler Apache::Reload
    PerlSetVar ReloadAll Off
</Files>
[download]

The first mod_perl example is a directory-oriented configuration; second, file-extension-oriented.