uniformdimesionevectordfield g error
 

I know this subject has been brought up before but I haven't found a remedy for it.
I'm doing simulations in rhoPisoFoam and I get this error message:

request for uniformDimensionedVectorField g from objectDirectory failed.
available objects of type uniformDimensionedVectorField g are
0
(
)
...

Someone mentioned the enviromentalProperties; should some textfile be modified to refer to this?
Thx for the help
R