Taxiways

Hi,
I am remaking the airport of Geneva (LSGG/GVA). I have added some taxiways but i get this problem:

In the FSSC program i get:

could somebody help me getting off the grass on the taxiways?
Thank you
William
I am remaking the airport of Geneva (LSGG/GVA). I have added some taxiways but i get this problem:

In the FSSC program i get:

could somebody help me getting off the grass on the taxiways?
Thank you
William