use strict;
use warnings;
use ID::Utilities;

use constant ARCHIVE => "http://www.us-cert.gov/control_systems/ics-ce
+rt/archive.html";

my $utils = new ID::Utilities;
my $html = $utils->getHTML( ARCHIVE );

my $vendor = "Rockwell Automation";
my $search_start = "<b>$vendor</b>";
my $search_end = "<p>&nbsp;</p>";

$html =~ m/($search_start.+$search_end)/i;
print $1;
[download]

I look at a bunch of modules including the one you you mentioned, but I do not understand how to use them. The documentations for the TreeBuilder modules (and other HTML parser modules) are above my current perl knowledge.

Data looks like this:

<p><b>RealFlex Technologies</b><br />Multiple Vulnerabilities in RealF
+lex RealWin, 
<a href="/control_systems/pdf/ICS-ALERT-11-080-04.pdf">ICS-ALERT-11-08
+0-04</a> 

(March 21, 2011)</p>

<p>RealFlex RealWin Multiple Vulnerabilities, 
<a href="/control_systems/pdf/ICSA-11-110-01.pdf">ICSA-11-110-01</a> 
(April 20, 2011)</p>

<p>RealWin Buffer Overflow, 
<a href="/control_systems/pdf/ICSA-10-313-01.pdf">ICSA-10-313-01</a> 
(November 09, 2010)</p>

<p>RealWin Buffer Overflows, 
<a href="/control_systems/pdf/ICS-ALERT-10-305-01.pdf">ICS-ALERT-10-30
+5-01</a> 

(November 01, 2010)</p>

<p>&nbsp;</p>

<p><b>Rockwell Automation</b><br />
Rockwell Automation ControlLogix Multiple PLC Vulnerabilities (UPDATE)
+, 
<a href="/control_systems/pdf/ICS-Alert-12-020-02A.pdf">ICS-ALERT-12-0
+20-02A</a> 
(February 14, 2012)</p>

<p>Rockwell Automation ControlLogix PLC Multiple Vulnerabilities, 
<a href="/control_systems/pdf/ICS-Alert-12-020-02.pdf">ICS-ALERT-12-02
+0-02</a> 
(January 20, 2012)</p>

<p>Rockwell Automation FactoryTalk RNADiagReceiver, 
<a href="/control_systems/pdf/ICSA-12-088-01.pdf">ICSA-12-088-01</a> 
(March 28, 2012)</p>

<p>Rockwell Automation FactoryTalk RNADiagReceiver (UPDATE),
<a href="/control_systems/pdf/ICSA-12-088-01A.pdf">ICSA-12-088-01A</a>
(April 06, 2012)</p>

<p>Rockwell Automation FactoryTalk RNADiagReceiver, 
<a href="/control_systems/pdf/ICS-ALERT-12-017-01.pdf">ICS-ALERT-12-01
+7-01</a> 
(January 17, 2012)</p>

<p>Rockwell FactoryTalk Diag Viewer Memory Corruption, 
<a href="/control_systems/pdf/ICSA-11-175-01.pdf">ICSA-11-175-01</a> 
(June 24, 2011)</p>

<p>Rockwell-PLC5, 
<a href="/control_systems/pdf/ICSA-10-070-02.pdf">ICSA-10-070-02</a> 
(March 11, 2010)</p>

<p>Rockwell RSLinx EDS, 
<a href="/control_systems/pdf/ICSA-11-161-01.pdf">ICSA-11-161-01</a> 
(June 10, 2011)</p>

<p>Rockwell RSLogix, 
<a href="/control_systems/pdf/ICS-ALERT-11-256-05.pdf">ICS-ALERT-11-25
+6-05</a> 
(September 13, 2011)</p>

<p>Rockwell RSLogix (UPDATE), 
<a href="/control_systems/pdf/ICS-ALERT-11-256-05A.pdf">ICS-ALERT-11-2
+56-05A</a>&nbsp; (September 19, 2011)</p>

<p>Rockwell RSLogix Denial-of-Service Vulnerability, 
<a href="/control_systems/pdf/ICSA-11-273-03.pdf">ICSA-11-273-03</a> 
(September 30, 2011)</p>

<p>Rockwell RSLogix Denial-of-Service Vulnerability (UPDATE), 
<a href="/control_systems/pdf/ICSA-11-273-03A.pdf">ICSA-11-273-03A</a>
+ 
(October 06, 2011)</p>

<p>RSLinx, 
<a href="/control_systems/pdf/ICSA-10-070-01.pdf">ICSA-10-070-01</a> 
(March 11, 2010)</p>

<p>RSLinx (UPDATE), 
<a href="/control_systems/pdf/ICSA-10-070-01A.pdf">ICSA-10-070-01A</a>
+ 
(May 03, 2010)</p>

<p>&nbsp;</p>

<p><b>RuggedCom</b><br /> 
RuggedCom Weak Cryptography for Password Vulnerability, 
<a href="/control_systems/pdf/ICSA-12-146-01A.pdf">ICSA-12-146-01A</a>
(June 18, 2012) 

<p>RuggedCom Weak Cryptography for Password Vulnerability, 
<a href="/control_systems/pdf/ICSA-12-146-01.pdf">ICSA-12-146-01</a> 
(May 25, 2012) </p>

<p>RuggedCom Weak Cryptography for Password Vulnerability, 
<a href="/control_systems/pdf/ICS-ALERT-12-116-01.pdf">ICS-ALERT-12-11
+6-01</a> 

(April 25, 2012)</p>

<p>RuggedCom Weak Cryptography for Password Vulnerability (UPDATE), 
<a href="/control_systems/pdf/ICS-ALERT-12-116-01A.pdf">ICS-ALERT-12-1
+16-01A</a>
(April 27, 2012) </p>

<p>&nbsp;</p>
[download]

I need to get all the advisories under Rockwell Automation... That is my goal, but I am having trouble being able to accomplish it. Any ideas on how to fix my regular expression?

The dot metacharacter (".") does not match newlines. See perlre for the /s modifier.

As an aside, your code is not really helpful as it includes a reference to a module that I don't have, ID::Utilities, and calls some method in there. If you're certain that the ->get method returns the correct HTML, why reference that method at all? Simply directly assign the HTML value in a test program, if only to eliminate misbehaviour of the ->get method, or of the remote end.