[GRASS-user] r.stream.basins error

[Francesco Mirabella]

Hi all,
I am trying to generate a basins map from a dem using r.stream.basins

I first cut the dem to the area I want to work on than run g.region to 
set the region to this map.
Then I calculated streams and streams flow directions with r.stream.extract.

In order to get stream basins I used r.stream.basins:
r.stream.basins  dir=rivers_flow    stream=rivers   basins=basins_rivers

The output gives an error saying:

Reading maps...
Calculate basins using streams...
Finding nodes...
ERROR: Stream and direction maps probably do not match
(Mon Oct 11 11:15:28 2010) Comando terminato (0 sec

Why do they not match if I derived them with the same command and from 
the same dem ? Am I doing something wrong ?

thanks in advance
Francesco