idw error in executing grid expression

Discussion created by giac85 on Apr 16, 2012
Latest reply on Apr 17, 2012 by slynch-esristaff
I have some issue to create IDW for 3 point features classes, here what happens whan I try to make IDW for one of those shp:

This is how IDW tool appears before I let it run (it's the same for the other 2 shapefile, it changes only the input point features, called 09 and 10):

I created the field yield_sped in the attribute table and I chose type  "double". The values in this field come from a division in the field calculator. Could be wrong for this reasons?