[R-sig-Geo] grid has empty column/rows warning

[G. Allegri]

Hi list,
what does this warning mean?

"Warning in points2grid(points,tolerance):
grid has empty columns/rows in dimension 1"

It gets out when doing an overlay between points and grid
[overlay(grid, pointsdataframe)], with sp package.

I receive a complete list of values for the points, uploaded from the
grid, but I don't know if I have to care about the warning...

Giovanni