#!/usr/local/bin/perl -Tw
use CGI::Carp qw(fatalsToBrowser);



print header();

$testUsername = param( "username" );
$testPassword= param( "password" );

open( PW, "password.txt" ) ||
die( "The database could not be opened." );
while ( $line = <PW> ) {
chomp( $line );
( $username, $password ) = split( ",", $line );
chop($password);
if ( $testUsername eq $username ){
$userVerified = 1;
if ( $testPassword eq $password ) {
$passwordVerified = 1;
}
}
}
close( PW );


print header();
print start_html("Checking password!");
if ( $userVerified&& $passwordVerified ) {
print "Permissionhas been granted, $testUsername .<br>";
print "Enjoy the site!< br>"
}
elsif ( $userVerified && !$passwordVerified ) {
print "You entered an invalid password. <br>";
print "Access has been denied. <br>";
}
else {
print "You have been denied access to this site.<br>";
}
print end_html();
[download]

You should also use the CGI line from the OP. In other words ADD the CGI::Carp line - don't replace the use CGI line,

And check the server logs if CGI::Carp doesn't help.

I think I've mentioned that once or twice already.

"What should it profit a man, if he should win a flame war, yet lose his cool?"

#!/usr/local/bin/perl -Tw
use CGI::Carp qw(fatalsToBrowser);

print header();

$testUsername = param( "username" );
$testPassword= param( "password" );

open( PW, "password.txt" ) ||
die( "The database could not be opened." );
while ( $line = <PW> ) {
chomp( $line );
( $username, $password ) = split( ",", $line );
chop($password);
if ( $testUsername eq $username ){
$userVerified = 1;
if ( $testPassword eq $password ) {
$passwordVerified = 1;
}
}
}
close( PW );


print header();
print start_html("Checking password!");
if ( $userVerified&& $passwordVerified ) {
print "Permissionhas been granted, $testUsername .<br>";
print "Enjoy the site!< br>"
}
elsif ( $userVerified && !$passwordVerified ) {
print "You entered an invalid password. <br>";
print "Access has been denied. <br>";
}
else {
print "You have been denied access to this site.<br>";
}
print end_html();
[download]