Hi Harry,

NSIS error may occur under one of the following conditions:
1. Software files downloaded from the Internet are not complete.
2. Downloaded software files have been modified from the original version.
3. Your PC is infected with a virus.
4. Physical media being used to install the program is damaged.
5. Required hardware (For example, CD/DVD drive) is malfunctioning.

You may do the following tasks to correct this:
Note: Try to install your software after each task.

1. Delete the cache of your Web browser. To do this, in the Microsoft Internet Explorer 8 window, open Tools menu and then select Delete Browsing History….Next, click the buttons to delete and also select the check box in the confirmation box that is displayed. Finally, click Yes to completely clear the browser cache.

Similarly you can delete in Chrome or Mozilla as well.

2. If available, download the update from another approved source.
3. Update your antivirus/Security software program.
4. Disable your antivirus program and any download accelerator tool on your computer, before performing the update.
5. Thoroughly scan your PC for possible virus or spyware infections.

As a last resort, the installer can be executed even though it's corrupted. To bypass the corruption test, pass /NCRC on the command line. To do so, go to Start->Run, type cmd and hit Enter. A black console window should open. Drag the installer into the window, hit Space and type /NCRC. Hit Enter again and the installer should start.

I hope this helps.

Regards,
Lokesh