Problem loading dplyr for Getting and Cleaning Data SWIRL practice

[Roy4323]

Please choose a course, or type 0 to exit swirl.

1: Exploratory Data Analysis
2: Getting and Cleaning Data
3: R Programming
4: Take me to the swirl course repository!

Selection: 2

| Please choose a lesson, or type 0 to return to course menu.

1: Manipulating Data with dplyr
2: Grouping and Chaining with dplyr
3: Tidying Data with tidyr
4: Dates and Times with lubridate

Selection: 1

| Attempting to load lesson dependencies...

| This lesson requires the ‘dplyr’ package. Would you like me to install it for you now?

1: Yes
2: No

Selection: 1

| Trying to install package ‘dplyr’ now...
Error in install.packages : Updating loaded packages

| Could not install package ‘dplyr’!
| | 0%Error in seq.default(0, 1, length.out = nrow(e$les)) :
argument 'length.out' must be of length 1

| Leaving swirl now. Type swirl() to resume.

install.packages(p, quiet = TRUE)
WARNING: Rtools is required to build R packages but is not currently installed. Please download and install the appropriate version of Rtools before proceeding:

https://cran.rstudio.com/bin/windows/Rtools/
Error in install.packages : object 'p' not found