iRules Can't call after responding - ERR_NOT_SUPPORTED (line 1) invoked from within "HTTP::host"

Hi,

I tried to write a irule that can response code 200 and some contenet when the query string matched.

But I found the error log as below :

TCL error: /Common/fz_stg_base <HTTP_REQUEST> - Can't call after responding - ERR_NOT_SUPPORTED (line 1) invoked from within "HTTP::host"

My irules as below :

when HTTP_REQUEST {
	switch -regexp [HTTP::query] {
	    "jsonp=NetTestCallback[0-8]&.+" {
			 HTTP::respond 200 content "Hello World!!"
		}
	}
}

/Common/fz_stg_company irule as below :

when HTTP_REQUEST {
	switch -glob [string tolower [HTTP::host]] {
	    "a.bc.xyz" {pool my_pool}
	}
}

My irules on the top order and fz_stg_company on the second order.

Any idea?