right or wrong cable?

i bought a rs-232 serial cable for to download software for my starview box because when i try to download the firmware the download box comes up but there is no download coming through,does the firmware need to be unzipped and if so how do i do this as i am totally new to computers,ii would very much appreciate the help i can get,thank you.

 

what type of cable it has to be a null modem cable (9pin female to female)

 

why is there a difference with the 1 i bought,because i have it connected both to my pc and my starview