Looking at the build output, I don't see the file acu410028_RelayManager.c being passed as a source file to the compiler. Not sure why this is the case, but for some reason the project appears to not be seeing it as a source file.
Was project created with an older version of CCS? Could you try importing the project into a new, clean workspace to see if that helps, or maybe even create a new project with CCS 5.5 and then add all the source files/build settings to it.