Hi
The 'rn' issue arises because (I guess) you downloaded Proforma from the osCommerce contributions website and then manually added FCKEditor afterwards.
It is the default FCK Editor behaviour to add these 'rn's, which are annoying to say the least. The free downloadable version of Proforma v0.1 on this website contains a slightly modified version of FCKEditor which does not have this problem.
Your best bet is to downlaod the full package from
here
and then copy ONLY the fckeditor folder over to your current installation. That way, its easier to keep what you've already saved on your DB.
The other option, of course, is to upgrade to the Premium version which has none of these problems and a whole lot more features besides
Good Luck.
Nick