Ive tried setting the __EVENTTARGET and am still getting the warning. I have changed the link number to vary the results with no luck. Here is my code

use strict;
use WWW::Mechanize;
use Time::Local;
use POSIX 'strftime';
use HTML::Strip;

my($url) = 'http://www.usgbc.org/LEED/Project/RegisteredProjectList.as
+px?CMSPageID=243&CategoryID=19&';
my($pageCheck) = "";
my $mech = WWW::Mechanize->new(autocheck =>1);
my($dirname) = "C:\\Program Files\\Perl Express\\Scripts\\";
my($fname) = "output.txt";
my($x) = 0;
open(OUT , ">$dirname$fname") || die "Cant open file";

#initialization to strip HTML from document
my $hs = HTML::Strip->new();

$mech->agent_alias('Linux Mozilla');

$mech->get($url) or die "Page $url can't be reached";
print "Made it past the url test\n";

my($form) = $mech->forms();
#selects all options from the lstLeedRating Field
my $menu = $form->find_input("lstLeedRating");


#clicks the BtnSearch
$pageCheck = $mech->click_button(name => "btnSearch");

my $pageCheck2 = "";

$pageCheck2 = $mech -> submit_form(
    with_fields => {
        '__EVENTTARGET' => 'dgRegProjectList:_ctl29:_ctl7',
        },
        );

    if($pageCheck2->is_success){

             print $pageCheck2->content;
             #print $pageCheck->content;
             }
        else {
             print STDERR $pageCheck2->status_line, "\n";
             die "Page with those fields not found!";
             }

        my $page = $mech->content;

    my $clean_text = $hs->parse( $page );

        $hs->eof;

    $clean_text =~s/.*(multiple LEED Rating Systems)//s;
        my @lines = split /\n/, $clean_text;
    for (@lines){
            s/^\s+//;
            s/\s+$//;
            s/\s+/ /g;
    }
        $clean_text =~s/(2  3  4).*//s;
        my @lines2 = split /\n/, $clean_text;
    for (@lines2){
            s/^\s+//;
            s/\s+$//;
            s/\s+/ /g;
        }
    my $clean = join "\n", @lines2;

    print OUT $clean;

        close OUT;
[download]

I have a feeling it has somethign to do with there call to the __doPostBack

<script language="javascript" type="text/javascript">
<!--
    function __doPostBack(eventTarget, eventArgument) {
        var theform;
        if (window.navigator.appName.toLowerCase().indexOf("microsoft"
+) > -1) {
            theform = document.frmRegisteredProjectList;
        }
        else {
            theform = document.forms["frmRegisteredProjectList"];
        }
        theform.__EVENTTARGET.value = eventTarget.split("$").join(":")
+;
        theform.__EVENTARGUMENT.value = eventArgument;
        theform.submit();
    }
// -->
</script>
[download]

Let me know what you think, and thanks in advance!