I just tried this from Solaris x86 2.7 to a NetBSD 1.5_ALPHA server, and
it doesn't have any problems.. so it looks like this is specific to
2.7 sparc clients.

The "value too large" (EOVERFLOW) errors usually mean that it can't handle
a 64bit size/offset value on an fs, because it has to store it 32 bits.
However, it is strange that this happens on 0 size files.

Could you perhaps send a tcpdump output of the transaction?
Something like

	tcpdump -i <your_interface> -s 1024 -vv port 2049

..on the NFS server.

- Frank