I had problems with one of the Nokia firmware tools that I found on the internet… I think I used the software detailed here
FAQ - FAQ - How can I recover/reset/restore my phone software? - Nokia - UK and it did it… the one I used first time round came up with an error similar to yours. Worth a try at least (from what I can see it's largely the same kinda program)
I think there's Software Updater and Software Recovery tool… This is the recovery tool. The software updater was the one that didn't work for me.