Assuming that you're running an Apache webserver, is it configured for Perl?

LoadModule cgi_module modules/mod_cgi.so
ScriptAlias /cgi-bin/ "/var/www/cgi-bin/"
<Directory "/var/www/cgi-bin">
    AllowOverride None
    Options None
    Order allow,deny
    Allow from all
</Directory>
AddHandler cgi-script .cgi .pl
DirectoryIndex index.html index.html.var index.cgi index.pl
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Update: Now that you've posted your form we can better diagnose. For example, your form's action sends it to "/home/anil/Desktop/displayPort.cgi". When you click "ClickMe", can the webserver access /home/anil/Desktop/displayPort.cgi? Does Apache's configuration file have a ScriptAlias /cgi-bin/ "/home/anil/Desktop/" line?