The NSIS errors 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:
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 Delete All button and also select the check box in the confirmation box that is displayed.
Finally, click Yes to completely clear the browser cache.
2. If the name of the downloaded installer files comprises multiple words, rename it to have only one word, say, SoftwareNameInstaller.exe.
3. If available, download the software installer file from another approved source.
4. Update your antivirus/Security software program.
5. Disable your antivirus program and any download accelerator tool on your computer, before performing the download.
6. Thoroughly scan your PC for possible virus or spyware infections.
Follow the link below to run the free online scan: http://onecare.live.com/site/en-us/default.htm The following thread discusses about removing viruses and malware online:
1. Open Command Prompt window, to do so, click start windows and in the search bar type cmd.exe and right click on it and run it as administrator.
2. Drag your installer file into this window.
3. Press the space key once and type /NCRC and then press Enter.
Hope it helps.
Thanks and Regards: Shekhar S - Microsoft Support.