One thing that stands out to me is:
if ($dbm1{"$accountAD"} && $dbm1{"$accountAD"} =~ /^$accountAD$/) {
The hash key, $accountAD, is being compared against the value of the hash, $dbm1{"$accountAD"}. Shouldn't $accountID be used somewhere in here?

sub generate_id {
  do { $accountID = join '', map { $chars[ rand @chars ] } 1..17; } 
  while grep {$_ eq $ID} my @used;
  print $ID;
[download]

 
$dbm1{$form{'usermail'}} = "$ID";
[download]

I think you're right and I changed $ID to $accountID but that wasn't the problem. $ID actually contained their registration number, I just had to rename ID to accountID to get the variables to work.

"Age is nothing more than an inaccurate number bestowed upon us at birth as just another means for others to judge and classify us"

sulfericacid

#!/usr/bin/perl -w

use strict;
use CGI::Carp qw(fatalsToBrowser);
use CGI;
use POSIX;
require SDBM_File;

#
# Define our constants
#

my $sendmail = "/usr/lib/sendmail";
my $adminmail = "test\@test.com";
my($verified, $unverified, $ID);
my @chars = ( "A" .. "Z", "a" .. "z", 0 .. 9, qw(! @ $ % ^ & * ) );

#
# Define our dynamic input
#
my $query = CGI->new;
print $query->header;
my %form = %{$query->Vars};
my $accountID = $query->url_param('accountID');
my $accountAD = $query->url_param('accountAD');
my (%dbm1, %dbm2);
my $dbm1 = "unverified.dbm";
my $dbm2 = "verified.dbm";

tie (%dbm1, 'SDBM_File', $dbm1, O_CREAT|O_RDWR, 0644)
   || die "Died tying database\nReason: $!\n";
   
tie (%dbm2, 'SDBM_File', $dbm2, O_CREAT|O_RDWR, 0644)
   || die "Died tying database\nReason: $!\n";   

#
# If form was completed generate an ID, store them to database, email 
+user
#

if ($form{'usermail'}) {
&generate_id;
&email;
  print "An email has been sent to $form{'usermail'} for verification.
+<br><br>\n";
$dbm1{$form{'usermail'}} = "$accountID";
}

#
# Or if url param's are present and checked add them to other DB and r
+emove them from $unverified
#

else {   
   my $unverified = $accountID;
   my $verified = "$accountAD";
   if ($dbm1{"$accountAD"} && $dbm1{"$accountID"} =~ /^$accountAD$/) {
 $dbm2{"$verified"} = "$accountAD";
      print "You have been added to the mailing list successfully!\n";
   } else {
      print "Registration failed!<br><br>\n";
      print "\$accountID: $accountID .<br>\n";
      print "\$accountAD: $accountAD .<br>\n";
   }
}

sub email {
$accountAD = "$form{'usermail'}";

open (MAIL, "|$sendmail -t") or die "Cannot access mail";
  print MAIL "To: $form{'usermail'}\n";
  print MAIL "From: $adminmail\n";
  print MAIL "Subject: Verify your Email Address\n\n";
  print MAIL "http://sulfericacid.perlmonk.org/evs/revised.pl?accountI
+D=$accountID&accountAD=$accountAD\n";
close (MAIL);
}

sub generate_id {
do { $accountID = join '', map { $chars[ rand @chars ] } 1..17; } 
while grep {$_ eq $ID} my @used;
  print $ID;

# my @unverified_emails=($form{'usermail'}, $accountID);
# $unverified = join "::",@unverified_emails;
#$dbm{"$unverified"}= join "::",@unverified_emails;
#foreach my $mail (split /::/, $dbm{'notverified'}) {
#  print "$mail is not verified!\n";
#}
}
untie(%dbm1);  
untie(%dbm2);
[download]

I think the problem is here

# if ($dbm1{"$accountAD"} 
#  && $dbm1{"$accountID"} =~ /^$accountAD$/) { # key values reversed
if ($dbm1{"$accountAD"} 
  && $dbm1{"$accountAD"} =~ /^$accountID$/) { # corrected
[download]

If it helps, here's code I used to debug your script, paste it in after the ties

# debug
sub showdata {
  my ($head,$data) = @_;
  print qq(<table border=1><tr><td> key </td><td> $head </td></tr>\n);
  foreach (sort keys %$data){
    print qq(<tr><td> $_ </td><td> $$data{$_} </td></tr>\n);
  }
  print q(</table>);
}

showdata("Unverified",\%dbm1);
showdata("Verified",\%dbm2);
[download]

poj
update ; Another way to fix it is to change these round

# $dbm1{$form{'usermail'}} = "$accountID";
$dbm1{"$accountID"} = $form{'usermail'};
[download]

I've tried all the suggestions you proposed, Poj, but the results aren't changing. I actually have been doing database prints to verify things are actually stored so they can be compared to. Things are storing as I expected them to so the only possible problem is with the verification which we concluded earlier.

Maybe what's confusing you is what's going on so I'll try to explain that small section.

AccountID is their generated $ID number which is a 17 character string. AccountAD is their email address collected from the form. Both of these are stored in the DB1 just fine. I'm trying to verify the url_params (accountID=xxx&accountAD=xxx) to what's being stored so I can add them to DB2.

That's what I am after anyways, is this what the code is actually doing or am I confusing that entire process? Thanks so much. sulfericacid

"Age is nothing more than an inaccurate number bestowed upon us at birth as just another means for others to judge and classify us"

sulfericacid