thats what I tried last night ( with all the firmware versions that netgear do for the DG834G v3 ) none and I mean NONE of them worked - just kept giving me that please contact your administrator error message.
Have tried uploading the firmware through the web gui on OS X as well as on windows ( when on windows I tried both the web gui and that utility ensuring I ran the rmdrv.exe or w/e and then the upgrade exe and I kept getting as far as selecting a NIC and then it just took me to the next screen which had a blank listbox and I could not get any further then that. )
I am from australia and we have these same modems DG834GSP v3. from a company called optus.
Like many others i tried various firmware and recovery methods but ultimatley it would always tell me to contact the administrator and the firmware cant be laoded.
then i came across this:
link Firmware link upgrade for DG834GSPV3 - Netgear - DSL Hardware - Whirlpool Broadband Forums
Netgear Modem Update
that page has the firmware that can be used, i have now succesfully upgraded the netgear to V1.04.13
So to all the software gurus out there download that file and look at the coding and i guess somewhere embedded in there is the permissions to allow the file to work.
This firmware has not fixed my sync issues, but im hoping someone out there can reverse engineer this file and make some decent firmware.