You mention that you have sub-files that are called by higher-level files. Are these sub-files in the same directory? If they are in a sub-directory to d:/Profiles/sal/Desktop/testFolder/, then the globbing won't pick them up.
You probably want to look into File::Find to traverse the directories and act on each blk file.
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