Migration XP- Window​s 7 DLL can't be loaded any more

Question

We have a Teststand sequence which uses a Labwindows CVI generated 32bit DLL called sensor.dll for doing its measurements
This works fine under XP using TestStand 4.2.1.  However starting the same sequence using the same sensor.dll  with  TestStand 4.2.1 on windows 7 64bit generates a -17004 error when trying to load that DLL.  During the first try it complained that msvcr90.dll is missing despite the MSVC++2008  runtime is installed in winsxs directory. If I copy  msvcr90.dll into a directory within ( directory search ) PATH, the messages about missing msvcr90.dll disappears, but the DLL still can't be loaded from TestStand ( without any hint to a missing dll) .
Looking at sensor.dll with Dependency Walker shows only two missing delay-load dependencies (on XP to IESHIMS.dll and  WER.dll, on Windows 7 to IESHIMS.dll and gpsvc.dll). I couldn't find any 32bit version of gpsvc.dll for windows7 so far, but that shouldn't matter because that's just a delay-load dependency.
The dependency to msvcr90.dll is brought in by another dll, which was build with MSVC++2008 and we checked the Manifest of that DLL and  couldn't find an error. 
The problem also exists with TestStand2012.
Ny questions are now: Why do I need to copy msvcr90.dll from its standard location in winsxs to another location on windows 7 but not on XP ? Any ideas what's going wrong when loading the dll on Windows 7 and how to debug that further ?  

Answer 1

How can I verify that the matching version for the MSVC++9.0  run time is installed ?
I did look into winsxs/manifest directory and found a manifest file containing.
<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
<assembly xmlns="urn:schemas-microsoft-com:asm.v1" manifestVersion="1.0">
    <noInheritable></noInheritable>
    <assemblyIdentity type="win32" name="Microsoft.VC90.CRT" version="9.0.21022.8" processorArchitecture="x86" publicKeyToken="1fc8b3b9a1e18e3b"></assemblyIdenti​ty>
    <file name="msvcr90.dll" hashalg="SHA1" hash="e0dcdcbfcb452747da530fae6b000d47c8674671"><a​smv2:hash xmlns:asmv2="urn:schemas-microsoft-com:asm.v2" xmlns:dsig="http://www.w3.org/2000/09/xmldsig#"><dsig:Transfor​ms><dsig:Transform Algorithm="urn:schemas-microsoft-com:HashTransform​s.Identity"></dsig:Transform></dsig:Transforms><ds​igigestMethod Algorithm="http://www.w3.org/2000/09/xmldsig#sha1"></dsigigestMethod><dsigigestValue>KSaO8M0iCtPF6YEr79P1dZsnom...> <file name="msvcp90.dll" hashalg="SHA1" hash="81efe890e4ef2615c0bb4dda7b94bea177c86ebd"><a​smv2:hash xmlns:asmv2="urn:schemas-microsoft-com:asm.v2" xmlns:dsig="http://www.w3.org/2000/09/xmldsig#"><dsig:Transfor​ms><dsig:Transform Algorithm="urn:schemas-microsoft-com:HashTransform​s.Identity"></dsig:Transform></dsig:Transforms><ds​igigestMethod Algorithm="http://www.w3.org/2000/09/xmldsig#sha1"></dsigigestMethod><dsigigestValue>ojDmTgpYMFRKJYkPcM6ckpYkWU...> <file name="msvcm90.dll" hashalg="SHA1" hash="5470081b336abd7b82c6387567a661a729483b04"><a​smv2:hash xmlns:asmv2="urn:schemas-microsoft-com:asm.v2" xmlns:dsig="http://www.w3.org/2000/09/xmldsig#"><dsig:Transfor​ms><dsig:Transform Algorithm="urn:schemas-microsoft-com:HashTransform​s.Identity"></dsig:Transform></dsig:Transforms><ds​igigestMethod Algorithm="http://www.w3.org/2000/09/xmldsig#sha1"></dsigigestMethod><dsigigestValue>tVogb8kezDre2mXShlIqpp8ErI...>
</assembly>
And looking into the dll, which introduces the dependency to msvcr90.dll  that dll includes a embedded manifest section with exactly the same values for name,version,processorArchitecture and publickeyToken.
So it looks for me that there is the matching version of msvc++ runtime installed ( with the installer , not by just copying it)