Error when creating a matrix in section 6.7 Real Case Study with HMSC: How Do Plant Traits Influence Their Distribution?

[mhb-bfg]

When I use the Whittaker revisit data to run this code:
for (i in 1:n){
for (j in 1:ns){
row = data$site==sites[i] & data$species==
species[j]
Y[i,j] = data[row,]$value
env[i] = data[row,]$env
trait[j] = data[row,]$trait
}
}
I encounter the following error:
Error in [<-(*tmp*, i, j, value = data[row, ]$value) : subscript out of bounds
whittaker revisit data.csv