I'm using Wix version 3.0.5419.0. I have two .wxs files, one which is a fragment, and another which uses the fragment to create the .msi file.

Here is the file which uses the fragment (DaisyFarmer.wxs):

    <?xml version='1.0' encoding='windows-1252'?>
<Wix xmlns='http://schemas.microsoft.com/wix/2006/wi'  xmlns:iis='http://schemas.microsoft.com/wix/IIsExtension'>
  <Product Name='Daisy Web Site 1.0' Id='BB7FBBE4-0A25-4cc7-A39C-AC916B665220' UpgradeCode='8A5311DE-A125-418f-B0E1-5A30B9C667BD'
    Language='1033' Codepage='1252' Version='1.0.0' Manufacturer='the man'>

    <Package Id='5F341544-4F95-4e01-A2F8-EF74448C0D6D' Keywords='Installer'
      Description="desc"
      Manufacturer='the man'
      InstallerVersion='100' Languages='1033' Compressed='yes' SummaryCodepage='1252' />

    <Media Id='1' Cabinet='Sample.cab' EmbedCab='yes' DiskPrompt="CD-ROM #1" />
    <Property Id='DiskPrompt' Value="the man" />

    <PropertyRef Id="NETFRAMEWORK35"/>
    <Condition Message='This setup requires the .NET Framework 3.5.'>
      <![CDATA[Installed OR (NETFRAMEWORK35)]]>
    </Condition>

    <Feature Id='DaisyFarmer' Title='DaisyFarmer' Level='1'>
      <ComponentRef Id='SchedulerComponent' />
    </Feature>

  </Product>
</Wix>

The fragment I'm referencing is (Scheduler.wxs):

<?xml version="1.0" encoding="utf-8"?>
<Wix xmlns="http://schemas.microsoft.com/wix/2006/wi">
  <Fragment>
    <DirectoryRef Id="TARGETDIR">
      <Directory Id="dir2787390E4B7313EB8005DE08108EFEA4" Name="scheduler">
        <Component Id="SchedulerComponent" Guid="{9254F7E1-DE41-4EE5-BC0F-BA668AF051CB}">
          <File Id="fil9A013D0BFB837BAC71FED09C59C5501B" KeyPath="yes" Source="SourceDir\DTBookMonitor.exe" />
          <File Id="fil4F0D8D05F53E6AFBDB498E7C75C2D98F" KeyPath="no" Source="SourceDir\DTBookMonitor.exe.config" />
          <File Id="filF02F4686267D027CB416E044E8C8C2FA" KeyPath="no" Source="SourceDir\monitor.bat" />
          <File Id="fil05B8FF38A3C85FE6C4A58CD6FDFCD2FB" KeyPath="no" Source="SourceDir\output.txt" />
          <File Id="fil397F04E2527DCFDF7E8AC1DD92E48264" KeyPath="no" Source="SourceDir\pipelineOutput.txt" />
          <File Id="fil83DFACFE7F661A9FF89AA17428474929" KeyPath="no" Source="SourceDir\process.bat" />
          <File Id="fil2809039236E0072642C52C6A52AD6F2F" KeyPath="no" Source="SourceDir\README.txt" />
        </Component>
      </Directory>
    </DirectoryRef>
  </Fragment>
</Wix>

I then run the following commands:

candle -ext WixUtilExtension -ext WiXNetFxExtension DaisyFarmer.wxs  Scheduler.wxs
light -sice:ICE20 -ext WixUtilExtension -ext WiXNetFxExtension Scheduler.wixobj DaisyFarmer.wixobj -out DaisyFarmer.msi

I'm getting an error when I run light.exe which says "DaisyFarmer.wxs(20) : error LGHT0094 : Unresolved reference to symbol 'Component:SchedulerComponent' in section 'Product:{BB7FBBE4-0A25-4CC7-A39C-AC916B665220}'."

What am I missing?