Deleting and rebuilding the configuration did not solve my CDT build error.
But excluding a file in my project did remove the CDT Build error. Of course the compile failed because the excluded file was needed. So I deleted the file link in my project and then re-linked the file into the project. The build process then completed successfully.
So there seemed to be some problem with the file linkage when I transitioned from CCS4 to CCS5. I had one other file in the build structure that was causing the same error. Deleting and then relinking the file fixed that file as well.