I had a problem with fields in Crystal Reports X where data driven textboxes would not grow to the right to accommodate the text length.  It would grow in Height and overlap a textbox that was placed directly below it.  It's important to note that the textboxes were both in the same section of the report (Details).  I solved this by splitting the section into Details a and Details b.  The sections would grow as the textbox grew and move the section below down, hence preventing the overlap.