booting via COM

Good day people. I want to boot Beagle Board via COM.
I have just succesfully uploaded x-loader.bin on my board (rev.C)
using pserial (Nishanth Menon's tools). And I am trying to upload u-
boot.bin using ukermit. The command "ukermit -p /dev/ttyS0 -f /home/
u-boot.bin" gives me: Failed after 4 retries in sequence 0 - success
send = 0 bytes Data transmit failed. I would be grateful to know if
anyone has experienced the same issue, or has any ideas about the