Package check result: ERROR

Check: examples, Result: ERROR
  Running examples in ‘robcp-Ex.R’ failed
  The error most likely occurred in:
  
  > base::assign(".ptime", proc.time(), pos = "CheckExEnv")
  > ### Name: cor_cusum
  > ### Title: A CUSUM-type test to detect changes in the correlation.
  > ### Aliases: cor_cusum
  > 
  > ### ** Examples
  > 
  > ### first: generate a time series with a burn-in period of m and a change point 
  > ###        k = n/2
  > require(mvtnorm)
  Loading required package: mvtnorm
  Warning in library(package, lib.loc = lib.loc, character.only = TRUE, logical.return = TRUE,  :
    there is no package called ‘mvtnorm’
  > n <- 500
  > m <- 100
  > N <- n + m
  > k <- m + floor(n * 0.5)
  > n1 <- N - k
  > 
  > ## Spearman's rho:
  > rho <- c(0.4, -0.9)
  >   
  > # serial dependence:
  > theta1 <- 0.3
  > theta2 <- 0.2
  > theta <- cbind(c(theta1, 0), c(0, theta2))
  > q <- rho * sqrt( (theta1^2 + 1) * (theta2^2 + 1) / (theta1 * theta2 + 1))
  > # shape matrices of the innovations:
  > S0 <- cbind(c(1, q[1]), c(q[1], 1))
  > S1 <- cbind(c(1, q[2]), c(q[2], 1))
  > 
  > e0 <- rmvt(k, S0, 5)
  Error in rmvt(k, S0, 5) : could not find function "rmvt"
  Execution halted

Check: tests, Result: ERROR
    Running ‘testthat.R’ [9s/9s]
  Running the tests in ‘tests/testthat.R’ failed.
  Complete output:
    > library(testthat)
    > #library(robcp)
    > 
    > test_check("robcp")
    Loading required package: robcp
    [ FAIL 2 | WARN 2 | SKIP 4 | PASS 252 ]
    
    ══ Skipped tests (4) ═══════════════════════════════════════════════════════════
    • On CRAN (4): 'test-Hodges_Lehmann.R:77:3', 'test-Wilcox.R:95:3',
      'test-huber_cusum.R:20:3', 'test-pKSdist.R:20:3'
    
    ══ Failed tests ════════════════════════════════════════════════════════════════
    ── Error ('test-CUSUM.R:57:3'): CUSUM test statistic is computed correctly ─────
    Error in `ginv(sigma)`: could not find function "ginv"
    ── Error ('test-cor.R:85:5'): CUSUM test for changes in the scale is performed correctly ──
    Error in `rmvt(k, S0, 5)`: could not find function "rmvt"
    Backtrace:
        ▆
     1. └─base::replicate(...) at test-cor.R:83:3
     2.   └─base::sapply(...)
     3.     └─base::lapply(X = X, FUN = FUN, ...)
     4.       └─robcp (local) FUN(X[[i]], ...)
    
    [ FAIL 2 | WARN 2 | SKIP 4 | PASS 252 ]
    Error: Test failures
    Execution halted