Not much options to do anything wrong, I think.
But maybe not all packages that you need for knitting are installed yet (?)
I think you need at least the package rmarkdown
because installing that will also install packages as knitr
and other packages. Did you install that?
You can see which packages are installed by typing in the R console:
installed.packages()[,1]
or checking the packages
panel.
From the packages
panel you can also install rmarkdown
and dependencies (make sure that the install dependencies
field is flagged).
You did not tell on what type of system your are working and maybe it is not relevant in this case.
Bit if installing missing packages does not work, it could become relevant.
Please inform us by copying the (first few lines of) the output of
sessionInfo()
in this message.