Firstly, I would just like to thank you for replying to my questions. The <dontrewrite> tag does indeed work, I was doing it wrong because I thought it was a normal HTML code where I had to open it with the tag, and close it with a </dontrewrite> tag. Once I moved it to the end of the post, it worked perfectly.
For now, I think I will try to work out the word.txt file some more, but what I do notice is that in order for the post to make any sense, I have to put so many entries into the word.txt, that the post is still considered a duplicate. A lot of the synonyms that are used do not make sense for those particular words. Is there any way to change which replacement words are available for certain words?
It appears that your program focuses on changing a lot of the smaller words: 'the,' 'and,' 'but,' etc...but a lot of those words are necessary in the context. Don't get me wrong, it's a great program, but the concept still requires a bit of work. Now, if there was a program that would automate the process, such as yours, but would allow the user to choose the synonyms to use, like wordflood, that would indeed be the end all rewriter..IMO.