I had the same problem.
Here's my code and it actually works! ;-)
The form-field "ToBBC" contained all the e-mail addresses seperated by a ","
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<%@LANGUAGE="VBSCRIPT"%>
<%
varToEmailBBC = Request.form("ToBBC"

varSubject = Request.form("Subject"

varFromName = Request.form("FromName"

varFromEmail = Request.form("FromEmail"

varMessage = Request.form("Message"

varHowMany = Request.form("HowMany"
' I later use the following variable for seperating the e-mails
varString = varToEmailBBC
Name = varFromName
SenderEmail = varFromEmail
Subject = varSubject
Body = varMessage
Set JMail = Server.CreateObject("JMail.SMTPMail"
'the name of your smtp-server
JMail.ServerAddress = "XXX.XXXX.XX"
JMail.Sender = Senderemail
JMail.Subject = Subject
response.write "Mail sent to:"
'for loop which adds all the recipient in the JMail-script
For i = 1 to varHowMany
SearchStr = ","
'MyPos = InstrRev(varString, SearchStr, -1, 1)
MyPos = Instr(1, varString, SearchStr, 0) - 1
MyString = Len(varString)
LeftString = Left(varString, MyPos)
JMail.AddRecipientBCC LeftString
RCount = Mystring - MyPos - 1
MyStr = Right(varString, RCount)
response.write "<br>"
response.write LeftString
varString = MyStr
Next
'****************
JMail.Body = Body
JMail.Priority = 3
JMail.AddHeader "Originating-IP", Request.ServerVariables("REMOTE_ADDR"
JMail.Execute
%>
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