After installing a Land F/X plugin, you're finding that your custom AutoLISP routines or scripts are not loading
This issue is likely occuring because your office incorrectly refined the S::Startup function using defun.
When refining the S::Startup function, take care to add to it via defun-q. For example, your current code may look like this:
It's also a LISP best practice to avoid having a customization file named acad.lsp. Instead, name your customization file after your firm's name or initials, which will identify it as your firm's cutomization file. For example, if your firm is called Billy Bob Landscape Architecture, you can name your customization file BBLA.lsp. Then make sure the code is intended as in the example above.