diff --git a/R/MakeBinomStack.R b/R/MakeBinomStack.R
index 6e56c51..a8b336e 100644
--- a/R/MakeBinomStack.R
+++ b/R/MakeBinomStack.R
@@ -26,7 +26,7 @@ MakeBinomStack=function(data, observs, tag="points", intercept=TRUE, mesh, presn
   if(length(presname)>1) stop("more than one name given for presences column")
   if(length(trialname)>1) stop("more than one name given for number of trials column")
   if(!presname%in%names(observs@data)) stop(paste(presname," not in names of presences data frame", sep=""))
-  if(!is.logical(observs@data[,presname]) & !trialname%in%names(observs@data))
+  if(!is.logical(observs@data[[presname]]) & !trialname%in%names(observs@data))
     stop(paste(trialname," not in names of presences data frame", sep=""))
 
   if(is.null(coordnames)) coordnames <- colnames(data@coords)
@@ -43,7 +43,7 @@ MakeBinomStack=function(data, observs, tag="points", intercept=TRUE, mesh, presn
   }
 
 # If presences are Boolean, reformat
-  if(is.logical(observs@data[,presname])) {
+  if(is.logical(observs@data[[presname]])) {
     observs@data[,presname] <- as.integer(observs@data[,presname])
     observs@data[,trialname] <- rep(1, nrow(observs@data))
   }