net::ERR_TOO_MANY_REDIRECTS

You don't need a redirect that creates the loop. Setting the URI and pool is enough if I undertand the requirement correctly. You might be able to simplify with switch cmd.

when HTTP_REQUEST {
        log local0."Hi-------------------" 
        set host [string tolower [HTTP::host]]
        set uri [HTTP::uri]
        if { $host equals "host1.com" and ($uri equals "") } {
            set uri "/newlga.nsf/frHomePage?" 
            log local0. "uri = $uri ******* " 
            HTTP::uri $uri
            pool PRD_landedgoods_Pool       
        }
        .............       
}