Does this help?
<update> Replying to comments has become tedious
No, it doesn't (implicit reply)
Try removing the setting that embeds the manifest
That fixes error, but absence of manifest causes program to fail
What is in xxx.rsx? Can you manually create a VS2008 project and move all the source there?
Is it possible without doing that? The source is OK, and looks like there are no errors in projects.
Build Log Build started: Project: MainFilter, Configuration: Release|Win32
Creating temporary file "c:\Depot\DVD Morpher 3.0\MainFilter\Release\RSP00000138203264.rsp"
with contents [ /outputresource:"..\Bin\Release\MainFilter.ax;#2" /manifest ".\Release\MainFilter.ax.intermediate.manifest" ]
Creating command line "mt.exe @"c:\Depot\DVD Morpher 3.0\MainFilter\Release\RSP00000138203264.rsp" /nologo" Output Window
Project : error PRJ0002 : Error result -1073741819 returned from 'C:\Program Files\Microsoft SDKs\Windows\v6.0A\bin\mt.exe'.
Results Build log was saved at "file://c:\Depot\DVD Morpher 3.0\MainFilter\Release\BuildLog.htm"
MainFilter - 1 error(s), 0 warning(s)
I'm a bit out of my depth here... how about starting with the second project (which has no dependencies?) and building that in VS2008? (just convert and build, no need to manually create vcproj)