dude i had a similar problem with the same error but i followed these instructions n i was able to flash emmc...

flasher-3.5 -F RX-51_2009SE_10.2010.19-1_PR_COMBINED_MR0_ARM.bin -f

change kernel with
flasher-3.5 -F RX-51_2009SE_1.2009.42-11_PR_COMBINED_MR0_ARM.bin' --flash-only=kernel -f

Restore emmc with vanilla
flasher-3.5 -F RX-51_2009SE_10.2010.13-2.VANILLA_PR_EMMC_MR0_ARM.bin' -f -R

hope it works for you