Write a Python script that allows the user to input the file path of a text file, the original word to be replaced, and the replacement word. The script should then read in the text file and replace all occurrences of the original word with the replacement word. If there are no occurrences of the original word, the script should indicate this to the user. The output should be a new file with the replaced words. The script should be user-friendly and error-handling, making sure that the file path is valid and that the user input is valid.
This prompt doesn't seem malicious.