multiple redirects - newb needs help

Try wrapping the condition you're NOT'ing in parentheses:

  
  when HTTP_REQUEST {  
     if { not ([string tolower [HTTP::host]] equals "www.domain.com") }{  
        HTTP::redirect https://www.domain.com  
     } else {  
        HTTP::redirect "https://[HTTP:host][HTTP::uri]" 
     }  
  }  
 

Or this way:

  
  when HTTP_REQUEST {  
     if { [string tolower [HTTP::host]] equals "www.domain.com" }{  
        HTTP::redirect https://[HTTP:host][HTTP::uri]  
     } else {  
        HTTP::redirect "https://www.domain.com" 
     }  
  }  
  

Also, because of a bug in the iRule parser in pre-v10 versions, make sure to always wrap // in double quotes. See SOL7988 for details:

SOL7988: The iRule parser may fail to correctly parse and load an iRule from the command line (Click here)

Aaron