unsure how to correct this error

[gg303]

I keep getting this error
Error in cmdscale(dist, k = k) : NA values not allowed in 'd'
I changes my NA values to zeros so I would not get a numeric error and not sure where to go from here! This is what I am trying

install.packages()
library("vegan")
data("fishGR")
dput(head(mydata, 100))
diversity(fishGR, index = "shannon")
fishGR[fishGR == 1] <- 10
fishGR[fishGR == 2] <- 100
fishGR[fishGR == 3] <- 1000
fishmat = as.matrix(fishGR[,16:16])
goodrows = which(rowSums(fishmat)!=0)
fishmat = fishmat[goodrows,]
NMDS1=metaMDS(fishmat, distance = "bray",k=2,trymax=100)

[startz]

I suspect you have done some more things that you haven't told us about. When I type

data("fishGR")

I get

Warning message:
In data("fishGR") : data set ‘fishGR’ not found

The code doesn't define myData.

And I don't see where you've changed NA values to zeros.

[gg303]

the fishGR is my data from an excel sheet, every number is either a 0, 1, 2, or 3. I changed it so it would show the zeros and not NA

[startz]

Just as a check you might try

any(is.na(fishGR))
any(is.na(fishmat))

although likely all that will do is be reassuring that you have indeed gotten rid of all the NAs.