Something to test. Change the password for the 'geoportal10' database user in the geoportal.xml file. (C:\Program Files\Apache Software Foundation\Tomcat 6.0\conf\Catalina\localhost) Then try a search. See if you get an error about connecting to the database. If you do then the portal is connecting to the Geoportal database (Postgress for you) and your problem is confined to AD.
Check this stuff. Items enclosed by < > are values I can't display. You AD distinguished names will of course be different.
<users
displayNameAttribute="sAMAccountName"
passwordEncryptionAlgorithm="SHA"
newUserDNPattern="cn={0},OU=<company>,DC=<domain>,DC=<company>,DC=com"
usernameSearchPattern="(&(objectclass=person)(sAMAccountName={0}))"
searchDIT="OU=<company>,DC=<domain>,DC=<company>,DC=com">
<requiredObjectClasses>
<objectClass name="top"/>
<objectClass name="person"/>
<objectClass name="organizationalPerson"/>
<objectClass name="inetOrgPerson"/>
</requiredObjectClasses>
<userAttributeMap>
<attribute key="username" ldapName="sAMAccountName"/>
<attribute key="password" ldapName="userPassword"/>
<attribute key="email" ldapName="mail"/>
<attribute key="firstName" ldapName="givenName"/>
<attribute key="lastName" ldapName="sn"/>
<attribute key="organization" ldapName="o"/>
<attribute key="affiliation" ldapName="businessCategory"/>
<attribute key="street" ldapName="street"/>
<attribute key="city" ldapName="l"/>
<attribute key="stateOrProv" ldapName="st"/>
<attribute key="postalCode" ldapName="postalCode"/>
<attribute key="country" ldapName=""/>
<attribute key="phone" ldapName="telephoneNumber"/>
</userAttributeMap>
</users>
<groups
displayNameAttribute="cn"
dynamicMemberOfGroupsAttribute=""
dynamicMembersAttribute=""
memberAttribute="member"
memberSearchPattern="(&(objectclass=group)(member:1.2.840.113556.1.4.1941:={0}))"
searchDIT="OU=Groups,OU=<city>,OU=Corporate,OU=<company>,DC=<domain>,DC=<company>,DC=com">
</groups>