in reply to Problem with CGI script

Your code syntax checks out OK but there are lots of errors, many in the HTML.
This code @rqstedtd = split(/&/, $rqst, 2); limits the split to 2 so $rqstedtd[3] is undefined.
This rewrite is untested but might help you a bit. Using CGI.pm makes life a lot easier !
use strict;
use warnings;
use CGI;

my $q = new CGI;
my $user     = $q->param('user');
my $password = $q->param('password');


# authenticate
my ($title,$body);
if ( &auth_user($user,$password) eq "OK" ){
  ($title,$body) = &validUser();
} else {
  ($title,$body) = &invalidUser();
};


# print html page 
print qq(Content-type: text/html\n
<html>
  <head><title>$title</title></head>
$body
</html>);

#
# == end of main program
#

#
# authenticate user/passwords
#
sub auth_user{
  my ($user,$password) = @_;
  open(PASS, "pass") or die "Couldn't find password file.\n";
  while(<PASS>){
    chomp;
    my ($u,$p) = split(/\t/, $_, 2);
    if ( ($u eq $user) && ($p eq $password) ){
      close PASS;
      return "OK";
    }
  }
  close PASS;
  return "notOK";
}

# valid
sub validUser {
  my $title = "Login successful !";
  my $body = q(<body bgcolor="black" text="red">
<h3>Login succesful!</h3><br><br>
<a href="www.eircom.net"><h2>Click here to continue</h2></a><hr>
</body>);
  return ($title,$body);
}

# invalid
sub invalidUser {
  my $title = "Login unsuccessful !";
  my $body = q(<body bgcolor="black" text="red">
Invalid username\password.<br>
Please try again.<br><br><hr>
<form method=POST action="file://C:\perl\login\password\login.cgi">
User Name:  <input name="user" size="30"><br>
Password:  <input name="pass" size="30"><br>
<input type="submit" value="Send"></form><hr>
</body>);
  return ($title,$body);
}

[download]
poj

In Section Seekers of Perl Wisdom