Office and Windows includes meta tag information when you copy and pastem as well as alternative versions for common characters eg the quote symbol ' . These are what cause the problem with the forums. Copying the text into notepad, for example, may not remove all these alternative characters.
What works for me is to save my document from word as a *.txt file. Select MS-DOS text file. Also selection the option to allow character substitution. This will replace all the alternative versions of characters with the common (old) ones.
Next, open the document in Notepad. Now copy from notepad and paste into the forum editor.
Cheers,
Stragen.