WIX won't copy DLL into system32 folder - wix

Question

I need to copy a DLL into the system32 folder, that's my WIX script but it doesn't work, the copy command just fails:
<?xml version="1.0" encoding="UTF-8"?>
<Wix xmlns="http://schemas.microsoft.com/wix/2006/wi"
xmlns:util="http://schemas.microsoft.com/wix/UtilExtension">
<Product Id="*" Name="LMBrick Service" Language="1033" Version="1.3.0.0"
Manufacturer="MyCompany" UpgradeCode="3de1a175-3701-435f-90bc-e97cb66b5524">
<Package InstallerVersion="200" Compressed="yes" InstallPrivileges="elevated" AdminImage="yes" InstallScope="perMachine" Platform="x64" />
<Property Id="MSIUSEREALADMINDETECTION" Value="1" />
<MajorUpgrade DowngradeErrorMessage="A newer version of [ProductName] is already installed." />
<Media Id="1" Cabinet="cab1.cab" EmbedCab="yes" />
<Feature Id="ProductFeature" Title="LMBrickServiceInstallation" Level="1">
<ComponentGroupRef Id="LMBrickComponents" />
</Feature>
<CustomAction Id="InstallLMBrickDll" Directory="LMBRICKINSTALLFOLDER" Execute="deferred" Impersonate="no"
ExeCommand="copy LMBrick.dll [System64Folder]LMBrick.dll"
Return="check" />
<InstallExecuteSequence>
<Custom Action="InstallLMBrickDll" After="InstallFiles">NOT Installed</Custom>
</InstallExecuteSequence>
</Product>
<Fragment>
<Directory Id="TARGETDIR" Name="SourceDir">
<Directory Id="ProgramFiles64Folder">
<Directory Id="Company" Name="MyCompany">
<Directory Id="App" Name="MyProduct">
<Directory Id="LMBRICKINSTALLFOLDER" Name="LMBrickService">
</Directory>
</Directory>
</Directory>
</Directory>
</Directory>
</Fragment>
</Wix>

Answer 1

Custom Actions that run Exes have to actually run an exe. However copy is not an exe; it's built into the command shell. So you have two immediate choices (and two better choices later):
Find an actual exe, such as xcopy.exe, and run that instead, or
Execute a shell such as cmd.exe with arguments that invoke its copy builtin.
You can confirm this by opening up a command prompt and executing the commands where copy and where xcopy respectively. Note that launching cmd.exe or any console program as an Exe will result in a console window flashing by during installation. This typically looks rather unprofessional, and you should use one of two alternatives:
Wrappers such as WixQuietExec can suppress the console window, or
Built-in Windows Installer functionality, such as exposed through CopyFile, can avoid the need for a custom action at all.
If possible, it's best to avoid custom actions and use Windows Installer functionality. So aim for the last option if you can.