title: 32-bit DLL "may not compatible" on Server 2008, but works on Server 2003
body: <p>We have a project that compiles to a 32-bit COM DLL and to a 64-bit COM DLL (the same one from <a href="https://stackoverflow.com/questions/4403501/how-do-i-install-both-32-bit-and-64-bit-versions-of-a-com-dll-and-auto-select">my earlier question</a>).  When I register both on my Windows 7 machine, both register successfully. When I register both on a Windows Server 2003 machine, both register successfully.</p>
  
  <p><strong>But</strong> when I try to register the DLLs on a Windows Server 2008 R2 standard SP1 machine, the 64-bit DLL registers successfully, but the <strong>32-bit</strong> DLL fails with the message (sic):</p>
  
  <p><strong>The module ""%1"" may not compatible with the version of Windows that you're running.
  Check if the module is compatible with an x86 (32-bit) or x64 (64-bit) version of regsvr32.exe.</strong></p>
  
  <p>I don't think a 32-bit DLL can be compatible with WS2003 and Win7 but not WS2008. That makes no sense.</p>
  
  <p>What might be happening?</p>