Sounds like there is an error in the command line. I am unfamiliar with NSIS though. A normal quiet mode MSI install command is:
msiexec.exe /I "C:\TestInstall.msi" /QN
Try to run the tool in this thread to help you deal with the MSI command line complexity: How to interactive a silently installing msi? (Progress data and cancel it) . It is a very effective tool called "Windows Installer Command Line Builder" from Wise Solutions. You can use it to experiment with the command line until it runs the way you want it to.
An msiexec.exe command line can become extremely complicated when you want to apply multiple transforms, set multiple properties and enable logging. Here is a sample:
msiexec.exe /I "C:\Installer.msi" /QN /L* "C:\logs\msilog.log" ALLUSERS=1 TRANSFORMS="C:\Transform.mst;C:\1031.mst"