From Anxious StsAdmi: dd does't work with tape drive?????

Dear fileutils maitainer:
	I'm a system administrator of a low-budget local network. I'm
trying to use tar/dump and ssh to do network backup to an Exacbyte VXA-1
external tape drive.
	When I issued following command

	tar cvf - temp | ssh cmtq8 "dd of=/dev/nst0 bs=64k"

	the system complains

	dd: writing `/dev/nst0': Invalid argument

	The curious thing is that by the time it complains and abort the
attempt it has already successfully tarred several files, which I can
retrieve.
	I can do tar/dump backup locally without problem, so it says
something about dd or the tape drive, or more precisely the compatibility
of the two.
	Is this a bug of dd? I'm using fileutils-4.1.9-11 on a redhat 7.1
box.
	Is there anyway I can get around this using utilities that comes
with linux to do network backup on tape drive?
	Thank you very much.
								Jiang