If d:/Profiles/sal/Desktop/testFolder/hi.bld/low.bld is a file, how can d:/Profiles/sal/Desktop/testFolder/hi.bld/low.bld also exist? A file can't be both a file and a directory, you know.
Perhaps you ment to drop the parent file's extension, as in
d:/Profiles/sal/Desktop/testFolder/hi/low.bld