Hey, sorry I have been quit busy. I ended up realizing we could do this all in one line and pop up a message box for you about the bad directory.
The attached code will check if the directory does not exist, and if it doesn't exist it will pop-up a message box warning you that the directory does not exist.
The code will continue to function and move on to the next file even if you don't click the message box. so you don't have to worry about this causing the script to stop functioning.