This most likely is due to a failed download. Just doing a quick google search on the 'NSIS Error' turns up some good info.
Source: http://www.instant-registry-fixes.org/how-to-resolve-nsis-error-messages/ is a good article that we suggest reviewing there are some good tips there.
As this is a digital download, there are some possibilities for this error to be seen.
The first is that the file is not downloaded completely 100% intact. If your connection is not solid, it can lead to impartial or incomplete file downloads. Especially on larger files. Try going to another location and downloading the installer and then performing an offline activation.
We recommend making sure you have a solid broadband connection. If you're using a slow connection such as a mobile phone hotspot or dial up is not recommended as this is the leading cause of failed or errors with downloads.
Make sure your anti-virus is temporarily disabled, consider right clicking the installer and clicking on "Run As Administrator"
Do a hard drive check on your system, if the hard drive has areas where data cannot be written, the system may throw this error. If you have another drive on your system, consider moving the installer to the other drive to attempt the install from.