you need to open the command line first. then type

cd C:\Program Files(x86)\Maemo\flasher-3.5\

then the flasher-3.5.exe -F RX-51_2009SE_20.2010.36-2_PR_COMBINED_MR0_ARM.bin -f

since your using 64bit you need to apply this when it says waiting for suitable device

http://wiki.maemo.org/Updating_the_t...nd_Workarounds

and straight away, DO NOT REBOOT, this is only if you want to flash your EMMC

flasher-3.5.exe -F <place emmc image name here> -f -R

but the two files need to be in the

C:\Program Files(x86)\Maemo\flasher-3.5\