I don't use Tomcat, but on a hunch it might be related to security, I did a google search on 'apache tomcat security "symbolic links"'. Here are a couple posts to other forums/mailing lists that it returned which looked promising.
If those things don't help, what about mounting the partition on your new hard drive directly onto $CATALINA_HOME/webapps/ROOT/djackman instead of using a symbolic link. (Disclaimer, I don't know Tomcat, and that may be a bad idea for some reason, but it seems like it should work. If the partition was mounted there, apache/tomcat should never know the difference.)