Blender.Load??

I am trying to use Blender.Load to make a .blend file load another .blend file from the folder (directory) ABOVE it. For example, making a .blend file in the C:/base/second/third/ directory load a file from C:/base/second/. I use the file pointer “…/(filename)”, because it has to work with other file paths, too. However, every time I try, Blender crashes. It works fine when loading files from the same directory as the active file.

And I know that loading another file will remove everything, that’s part of what I want to accomplish. But the loaded file must be in the above directory.

Any suggestions / explanations?