Unfortunately the link to the picture doesn't work, so I am guessing as to what your preview looked like... however, looking at what you posted in that topic, I have come across some strange behaviour which I think is probably the same. A quick glance at the code shows that a cookie is used to pass the message to pop_preview.asp. i.e. in post.asp
function OpenPreview()
{
var curCookie = "strMessagePreview=" & escape(document.PostTopic.Message.value);
document.cookie = curCookie;
popupWin = window.open('pop_preview.asp', 'preview_page', 'scrollbars=yes,width=750,height=450')
}
and in pop_preview.asp
<%
strMessagePreview = Request.Cookies("strMessagePreview")
Response.Cookies("strMessagePreview") = ""
This is likely to be causing a problem with large posts. According to MSDN,
A more significant problem is the size limitation. The maximum allowable size of a cookie varies with different browsers, but all browsers support cookies of at least 4,096 bytes.
So it seems a different method is probably needed here.
Regards
Steve