YAMON install

I've attempted to install NetBSD onto a MIPS Malta 4Kc board. Using  
the YAMON ROM monitor I've loaded "netbsd.srec-ALTA" via a tftp  
server. However, when I type "go" at the YAMON prompt I eventually  
end up with some of the following messages:

wd0: no disk label
vfs_mountroot: can't open root device
cannot mount root, error = 6

There is no reference to partition "wd0" when I prompt for disk  
information only "hda" references. there appears to be some  
discrepancy between the disk partitions NetBSD expects and what YAMON  
says exists. The LED on the board displays "NetBSD" so it appears to  
be trying to do an installation.

I'm using the evbmips-mipsel 3.0.1 download.

Any help would be appreciated.

Regards,
Laurence