Static analysis with Dependency Walker is sometimes useless. You have to run the process with Dependency Walker. Open perl.exe in Dependency Walker, then click on the "Profile" menu bar item, then click "Start Profiling". Dep Walker will run the perl process, and you will have a log of all manifest activity, static and dynamic (LoadLibrary) DLL loads or misses.

R6034
An application has made an attempt to load the C runtime library incor
+rectly.
Please contact the application's support team for more information
[download]

means there was no manifest on the (XS or database) DLL that tried to load msvcr80.dll. The error comes from MS's code in DllMain that is static linked into every VS 2005 DLL as part of the C library.

I gather that the problem is some incompatability between the MSVC runtime libraries that Perl.exe expects and what it finds, as there are a number of posts about sticking MSCVR80.dll or perl.exe.manifest files in the perl/bin directory to make the interpreter happy. I have tried many iterations of this, and I am convinced that I have compatible versions of MSVCR80.dll and a manifest describing it that Perl.exe can find, but I still get this same set of errors.

Unlike in the old days with SxS you can NEVER stick a SxSed DLL in PATH and expect it to work (there is local redirection but I've never been able to make it work). It has to be in C:\WINDOWS\WinSxS under one of those crypto hashed folders.