Mod_proxy apache balance to 1 Tomcat app works, fails with another?

[Bob Kimble <ki...@4j.lane.edu>]

I am a newbie to Tomcat. I am tasked with deploying a couple of 
applications from our software vendor. I am an Oracle DBA, not a software 
developer, so this question is probably very rudimentary. I have read the 
'Tomcat Definitive Guide', and used it to set up load balancing for the 2 
applications the software company developed. The applications work fine 
standalone, but we have 3 application servers I am trying to load balance.

I am using apache's mod_proxy to load balance 3 tomcat servers that have 2 
different apps on them. One of the applications works fine, but the other 
one gives a 404 error. To make sure it was load balancing correctly, I 
installed an instance.txt in the application's directories -  webapps/aalTA 
and aal_pa. When I try the aal_pa application, I see the load balancing is 
working correctly. When I try the aalTA application instance.txt, again I 
get the 404 error. I can get to both applications directly, so all is 
working there.

When I go to the aalTA application using the load balancing, the error 
message from Tomcat is
"The requested resource 
(/aalTA/servlet/LayoutMgr%3FLAYOUT=/aal/aalApp1_login/instance.txt) is not 
available."

When I go to http://sisapp4:8080/aal_pa/ directly, the URL does not change. 
When I go to http://sisapp4:8080/aalTA/  directly, it automatically adds 
"servlet/LayoutMgr?LAYOUT=/aal/aalApp1_login" to the end of the URL.

Is there something I can do to make this work, or is it just that this 
application cannot work with Apache load balancing?

Platform: Redhat Enterprise Linux 4
Apache Version: 2.2.9
Tomcat Version: 5.5.25