What is the quantity of physical memory in the machine and what is the OS version?
By default, Windows Server and Windows in general create a hiber.sys file on the system which generally takes an equal amount of space in GB to the quantity of RAM on the system.
You might need to open a command prompt as administrator (right-click; runas administrator).
In the elevated prompt:
powercfg -H off
This will turn off the hibernation feature of the OS and free up the disk space the system is using.
Alternatively, if you have an additional partition, D: drive for example, you can also change the location of the pagefile from the default C: partition.
Of course both mentionned techniques for freeing up disk space are relative to the fact that the files you require for LUA are located on the C: drive.