Rule that redirects based on length of [HTTP::uri]

Honestly, I'm not sure how your rule was working on 4.x becuase the http_uri value is a string and you are comparing it to a number. What you want is the string length. This should work for you using the builtin "string" TCL command.

when HTTP_REQUEST {
  if { [string length [HTTP::uri]] > 1 } {
    use pool siebelqa
  } else {
    HTTP::redirect "http://[HTTP::host]/fins_enu/"
  }
}

Note, I added an extra slash in your redirect after the HTTP::host value. I was assuming you are redirecting to the same host with the /fins_enu/ path. If you are trying to append "fins_enu/" to the host value then leave it as is.

BTW, you could make the rule much simpler if you set the default pool on your virtual server to "siebelqa". Then your rule could look like this

when HTTP_REQUEST {
  if { [string length [HTTP::uri]] == 1 } {
    HTTP::redirect "http://[HTTP::host]/fins_enu/"
  }
}

-Joe