um yeah, I selected "Browse..." to try all the .bin files I downloaded. I tried with these 4 files:

RX-34_2007SE_4.2007.26-8_PR_COMBINED_MR0_ARM.bin
RX-34_2007SE_4.2007.38-2_PR_COMBINED_MR0_ARM.bin
RX-34_2008SE_1.2007.44-4_PR_COMBINED_MR0_ARM.bin
RX-34_2008SE_2.2007.50-2_PR_COMBINED_MR0_ARM.bin

and got the exact same "The software on your Nokia N800 was not updated, because the update file is not supported by your device" for every one. There was not a problem with getting the update program to detect the N800; it just refused to install any N800 .bin to the device.