RTF file problems	WinWord says it cannot open a file: A common reason in Word 97 is that the font table is too big. There is a macro to clean the font table. This removes all but the really necessary fonts. 
RTF file problems	RoboHelp crashed and cannot open a file. This happens if the file has been corrupted without being so damaged that Word complains. The best thing to do is, make a new doc, copy the contents of the file into the new doc. Then save the new file "As WinHelp RTF". This is a new file filter in Word 97. 