help - r.mapcalc

[Pedro Franco Sequeira]

Hi GRASS users,

I can't make r.mapcalc work. 

I am always getting the message :

WARNING: opencell: - illegal file name
OOPS can't create cell file <>

to the the line    result = soils + streams

It seams that G_open_cell_new() is receiving a Null name. I tried adding
spaces, quotes, erased all spaces, but it refuses to work.

Any help would be much appreciated. Thanks in advance.

Pedro