> I am developing a FUSE based filesystem in Linux. I received
> a patch from Antti Kantee porting it to NetBSD. Now, I want
> to support this platform.
> 
> So, I tried to install NetBSD 3.1
[snip]

I've not looked at your xen problem, but you need to use -current if you 
want to use refuse/puffs. You'll also need to build from source rather than 
one of the daily auto-builds as puffs isn't enabled by default. I would 
start off with an autobuild though and make sure you use the right 
XEN3_DOMU kernel.