I found it !!
active.asp*
Around line 127 find this code :
if Request.Form("AllRead") = "Y" then
'## The redundant line below is necessary, don't delete it.
Session(strCookieURL & "last_here_date") = Request.Form("BuildTime")
Session(strCookieURL & "last_here_date") = Request.Form("BuildTime")
lastDate = Session(strCookieURL & "last_here_date")
UpdateLastHereDate Request.Form("BuildTime"),strDBNTUserName
ActiveSince = ""
end if
CUT this code .. we don't need it here, but we do need it somewhere else
privatemess.asp*
Around line 190 find this code :
ActiveTopicCount = -1
PASTE the code that you cut from active.asp immediately before this line.
* these line numbers relate to the Image Forum MOD, but solve the common problem when you have the Active Topic counter at the top of the page