Use single quotes instead of FALSE.

R-package/R/save_files.r

@@ -52,5 +52,5 @@ save_kml <- function(outPath, step, raster, overwrite) {
                                crs = "+proj=longlat +datum=WGS84",
                                method = 'ngb')
   
-  raster::KML(kml, paste(outPath, paste("step_", step, sep = ""), sep = ""), overwrite = overwrite, zip = FALSE)
+  raster::KML(kml, paste(outPath, paste("step_", step, sep = ""), sep = ""), overwrite = overwrite, zip = '')
 }