Getting error: Unable to open merge module '...msm'. Check to make sure the module language is correct

My goal is to include the OPC COM ProxyStub MergeModule (x64) in my msi. I am using WiX. I tried following the example code for How To: Install the Visual C++ Redistributable with your installer.

Here is my Product.wxs:

<?xml version="1.0" encoding="utf-8"?>
<Wix xmlns="http://schemas.microsoft.com/wix/2006/wi" ...>
  <Product Id="*" Name="..." Language="1033" Version="..." Manufacturer="..." UpgradeCode="...">
    ...  
    <DirectoryRef Id="TARGETDIR">
        <Merge Id="OPCRedist" SourceFile="OPC COM ProxyStub MergeModule (x64).msm" DiskId="1" Language="0"/>
    </DirectoryRef>
    <Feature Id="OPCRedist" Title="OPC Core Components" AllowAdvertise="no" Display="hidden" Level="1">
        <MergeRef Id="OPCRedist"/>
    </Feature>
  </Product>
  ...
</Wix>

When I compile the wixproj I get the following error:

Unable to open merge module 'OPC COM ProxyStub MergeModule (x64).msm'. Check to make sure the module language is correct. 'The language of this installation package is not supported by your system. (Exception from HRESULT: 0x80070657)'

How do I get rid of that error?

Changing Language="0" to Language="1033" got rid of the error. I'm not sure if this is correct.