Running examples in ‘nlreg-Ex.R’ failed
The error most likely occurred in:

> base::assign(".ptime", proc.time(), pos = "CheckExEnv")
> ### Name: Dmean
> ### Title: Differentiate the Mean Function of a Nonlinear Model
> ### Aliases: Dmean
> ### Keywords: nonlinear
> 
> ### ** Examples
> 
> library(boot)

Attaching package: ‘boot’

The following object is masked from ‘package:survival’:

    aml

> data(calcium)
> calcium.nl <- nlreg( cal ~ b0*(1-exp(-b1*time)), 
+                      start = c(b0 = 4, b1 = 0.1),  data = calcium )
> Dmean( calcium.nl )
function (b0, b1, logs, ...) 
{
    .expr3 <- exp(-b1 * time)
    .expr4 <- 1 - .expr3
    .expr6 <- .expr3 * time
    .value <- b0 * .expr4
    .grad <- array(0, c(length(.value), 2L), list(NULL, c("b0", 
        "b1")))
    .hessian <- array(0, c(length(.value), 2L, 2L), list(NULL, 
        c("b0", "b1"), c("b0", "b1")))
    .grad[, "b0"] <- .expr4
    .hessian[, "b0", "b0"] <- 0
    .hessian[, "b0", "b1"] <- .hessian[, "b1", "b0"] <- .expr6
    .grad[, "b1"] <- b0 * .expr6
    .hessian[, "b1", "b1"] <- -(b0 * (.expr6 * time))
    attr(.value, "gradient") <- .grad
    attr(.value, "hessian") <- .hessian
    .value
}
> ##function (b0, b1, logs)
> ##{
> ##    .expr3 <- exp(-b1 * time)
> ##    .expr4 <- 1 - .expr3
> ##    .expr6 <- .expr3 * time
> ##    .value <- b0 * .expr4
> ##    .grad <- array(0, c(length(.value), 2), list(NULL, c("b0",
> ##        "b1")))
> ##    .hessian <- array(0, c(length(.value), 2, 2), list(NULL,
> ##        c("b0", "b1"), c("b0", "b1")))
> ##    .grad[, "b0"] <- .expr4
> ##    .hessian[, "b0", "b0"] <- 0
> ##    .hessian[, "b0", "b1"] <- .hessian[, "b1", "b0"] <- .expr6
> ##    .grad[, "b1"] <- b0 * .expr6
> ##    .hessian[, "b1", "b1"] <- -(b0 * (.expr6 * time))
> ##    attr(.value, "gradient") <- .grad
> ##    attr(.value, "hessian") <- .hessian
> ##    .value
> ##}
> ##
> param( calcium.nl )
Error in UseMethod("param") : 
  no applicable method for 'param' applied to an object of class "c('nlreg', 'nls')"
Calls: param
Execution halted