i'm an idiot. i spent like 15 minutes debugging this.

utils/he_ipv6/example.tunnelbroker.xml

@@ -12,15 +12,16 @@
   <creds>
     <!--
     Credentials are kept separate from tunnel configuration because you can have multiple (up to 5) tunnels per user.
-    The updateKey is *not* your password! You can find it in the "Advanced" tab of your tunnel's configuration on
-    your tunnelbroker.net panel.
+    You can find the updateKey in the "Advanced" tab of your tunnel's configuration on your tunnelbroker.net panel.
     -->
     <cred id="ipv6user">
       <user>ipv6user</user>
+      <password>someSecretPassword</password>
       <updateKey>xXxXxXxXxXxXxXXX</updateKey>
     </cred>
     <cred id="anotheruser">
       <user>someotheruser</user>
+      <password>anotherPassword</password>
       <updateKey>0000000000000000</updateKey>
     </cred>
   </creds>
@@ -28,14 +29,11 @@
     <!--
     Each tunnel MUST have an "id" and a "creds" attribute. The "creds" attribute should reference an "id" of a
     creds/cred object.
-    The tunnel ID can be found by logging into your tunnelbroker.net pannel, clicking on the tunnel you wish to use, and
+    The tunnel ID can be found by logging into your tunnelbroker.net panel, clicking on the tunnel you wish to use, and
     looking at the URL in your browser.
     It is in the format of https://www.tunnelbroker.net/tunnel_detail.php?tid=[TUNNEL ID]
     So if it takes you to e.g. https://www.tunnelbroker.net/tunnel_detail.php?tid=12345, your tunnel ID would
     be "12345".
-    The below directives give you a Section and Value Name. This refers to the tunnelbroker.net panel page for the
-    specific tunnel you're configuring. e.g. To use the above example, this information is found at
-      https://www.tunnelbroker.net/tunnel_detail.php?tid=12345
     -->
     <tunnel id="12345" creds="ipv6user">
       <!--