parpool is a function in the Parallel Computing Toolkit, which is an optional toolkit that you would need to have a license for and would need to install.
You can use
license('test','Distrib_Computing_Toolbox')
to determine whether you are already licensed for the product but might not have it installed, and you can use
ver
to determine whether you have it installed (but possibly not licensed.)
Note: Parallel Processing Toolkit is not included in the usual Student Version license either.