expression string

[Roman Meier]

Hi list

I've got a problem using the same expression string multiple times. It seems
that a can use a specific expression only one single time within a map-File.
When I use it a second time mapserver (4.0.2 and 4.2.5) returns an empty
page. Is it possible to use the same expression multiple times?

I'm using the following expression:

[...]
  CLASS
        NAME "blabla"

        EXPRESSION ('[SYSTEM]' eq 'Schmutz')

        TEMPLATE "template/schacht.html"
[...]


Any ideas? Thanks in advance!
Roman