debugging TUX

There isn't much documentation on this so I was hoping to get some
information from here.  We're seeing some strange and inconsistant
behaviour with the files TUX serves.  Our setup is normal; TUX on
port 80, apache on 8080.  With TUX logging on we see that some
static pages that TUX should be serving are in fact passed to apache.
The status code is -1 in the TUX logs, and we can see the request in
apache's common log.  Is there some way to find out why TUX is
passing the request to apache ?

thanks,
M