The other thing worth checking is: print keys %$pointer; just to see if having Login capitalized in the $user2 assignment is a problem (as it's all lowercase in the SELECT statement).

According to the Perl DBI book, some database drivers convert field names to all uppercase or all lowercase. You can coerce DBI into fixing this for you with the following modification: $pointer = $sth->fetchrow_hashref('NAME_lc'); That will make the hash keys all lowercase. 'NAME_uc' makes them all uppercase. 'NAME' is the default, doing no mangling at all.

Another reason you could get an uninitialized value warning is if the field is NULL. Before using database fields, you should make sure they have a value to avoid the message.

print $value if (defined $value);
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# do a $dbh = DBI->connect(...)
$dbh->{'RaiseError'} = 1;
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Also, try dumping out the hashref that you're getting back:

use Data::Dumper;
while ($pointer = $sth->fetchrow_hashref) {
    print Dumper $pointer;
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Anyways, I stayed up all night trying to figure it out. I even re-wrote the entire script. It worked fine until, as I mentioned, started adding more fields to that loop.

my $username = param("username");
my $password = param("password");
my $user2;
my $pass2;
my $name;
my $client;

&Create_DB_Connection;

$SQL = "SELECT name, clientid, login, password FROM Client WHERE login
+='$username' AND password='$password'";

&Do_SQL;

while ($pointer = $sth->fetchrow_hashref)
{
    $user2 = $pointer->{'Login'};
    $pass2 = $pointer->{'Password'};
    $name = $pointer->{'name'};
    $client = $pointer->{'ClientID'};
}
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one way to solve it is to assign a default value right away when you declare variables with my.

ie:

$user2 ="user2";
$pass2 ="*****";
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no warnings;
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