Ok thanks for the screen grab, that shows that your Mac is talking to the modem and that the IPs must have been correct.
>>> it doesn't do anything like its not connected to the internet etc....
It doesnt need to be connected to the internet, it just needs to be able to communicate with your PC. I always disconnect (unplug) mine from the internet when doing any firmware upgrades.
You should have SP10 on your PC ready to upload from your machine direct to the modem.
From what you said so far, it sounds like the reset procedure isnt working, which is what you need to do to get to the F/W upload page.
Another 'just checking' you are only using just LAN2 whilst trying to do the upload and youre not using the double cables and no router in between like you would to get stats? - Sorry if that was an obvious.
I'll leave this post here a little bit longer so you can read my response, but in a bit I'll split it off to forum its own topic and move to the routers section where one of the other guys may be more likely to spot it and come up with some other suggestions.