"Your request produced an error."

Thanks for your replies concerning the JVM monitoring. Here's my next 
one already:

I'm successfully deploying an WO app on our new Solaris machine. Now I 
tried adding a second one (3. one to be exact when counting 
JavaMonitor). Unfortunately this time all I get is this:

Your request produced an error.

Neither the adaptor log nor the app log contain any error messages. The 
app seems to be up and running. We just don't get any output. :-(

Has somebody encountered this already? Any ideas where to dig?
Thanks!

-Will