error while using own columns for R plots

I got the following example from the R view node:

 

 x <- seq(0, 50, length= 50)
 y <- x
 f <- function(x, y) { r <- sqrt(2*x+10*y); cos(r)*x/r}
 z <- outer(x, y, f)
 persp(x, y, z, theta = 30, phi = 30, expand = 0.5, col = "lightblue")

 

this works fine. how can I put my own colums in there?

 

when I use:

 x <- R$"Col0"
 y <- x
 f <- function(x, y) { r <- sqrt(2*x+10*y); cos(r)*x/r}
 z <- outer(x, y, f)
 persp(x, y, z, theta = 30, phi = 30, expand = 0.5, col = "lightblue")

 

I get the error:

ERROR     R View (Local)     Execute failed: Execution of R script failed: Calls: persp -> persp.default

 

I get the same error nearly on all the R functions. So I thnik I have to transform the column anyhow?

Need help! Thanks!!