There is a new ugly feature in
Tomcat 5.xx

When your web-application have been deployed, Resource reference created for each context, but this referrence have an empty value of URL and DriverClass name.
You have to describe an additional reference to Resource for each HOST and context. You can use Tomcat admin interface and repeat resource description from general section (Resources->Data Sources) in context related Tomcat (Server->Service->Host(yourhost)->Context(/sccm)->Resources->Data Sources). But you will have to repeat it after every deployment

Another way is creation an additional web.xml file in folder "Tomcat 5.xx\conf\Catalina\yourhost\web.xml" with description of resource for your context like follow:
<Context displayName="CNTX" docBase="web" path="/web" workDir="work\Catalina\localhost\web">
<Resource auth="Container" description="" name="jdbc/license" type="javax.sql.DataSource"/>
<ResourceParams name="jdbc/license">
<parameter><name>url</name><value>jdbc:mysql://localhost:3306/licenses?autoReconnect=true</value></parameter>
<parameter><name>driverClassName</name><value>com.jdbc.mysql.Driver</value></parameter>
</ResourceParams>
</Context>