Using X-Forward iRule and get Operation not supported

hi all,

I have the following iRule (see below) that generates the following error on some web pages:

 
 Jul  2 09:58:14 tmm tmm[9998]: 01220001:3: TCL error: X_Forwarded_For_Client_IP  - Operation not supported (line 1)     invoked from within "HTTP::header insert X-Forwarded-For [IP::remote_addr]" 
 

Now, this particular web page -- we have a rule above it in order that was redirecting from http to https. I thought that might of been the issue but I'm seeing this on another web page. I'm still think another rule might be stepping on it but I cannot say for sure.

I'm running version: BIG-IP 9.4.5 Build 1049.10 Final

Thanks in advance for your responses

** iRule **

 
  5/15/09  
  rewrites the Client IP address into the REMOTE_ADDRESS field so IIS logs 
  can see the true client IP address and not the F5 IP address. 
  (NOTE: Must add ISAPI filter to the IIS web site and enable Insert XForwarded For  
  on the HTTP profile for this to work) 
  
  
 when HTTP_REQUEST { 
 HTTP::header insert X-Forwarded-For [IP::remote_addr] 
 }