Error BITBAKE

[emanuele bottegoni]

Hello,

at this time I've tried to follow the linux4sam getting started to build
an
angstrom,http://www.linux4sam.org/twiki/bin/view/Linux4SAM/OpenEmbeddedAngstromBuild

When I type bitbake angstrom-minimal-image, under root, it tells me I have
to operate as user.
So I Logon as user but running the same command (bitbake ang...)I obtain a
at start An Handling Bitbake Files (.../4650) and then the following errors:

- IOError:[Errno 13] Permission
denied:'/stuff/tmp/cache/at91sam9263ek/bb_cache.dat'


WHAT'S WRONG?