Both mozilla and opera accept cookies, its not that.
There are about 15-20 other variables in the session, but only the card details fail to remain in the session.
For instance, if do
<%=(
String)session.getAttribute("name")%>
<%=(String)session.getAttribute("cardtype")%>
on step4.jsp, they will both display a value (meaning they both have been set!).
But then on step5.jsp, if i do the same, ONLY the first one will have a value (ie "name"), "cardtype" will be null. But, again, this only happens with Mozilla and Opera, in IE, it works fine.