>This code is almost 2 years old, so maybe the IE5 OE works differently now, but in IE4 with OE I have this method fragment in production:

I used MSExchange. But I found the FAQ, and it says you HAVE TO update the AttachmentPosition property, check out the link.

SYMPTOMS

When attaching multiple file attachments using the MSMAPI32 OCX, calling
the Send method causes the following error to occur:

CAUSE

The AttachmentPosition property of the MAPIMessage control is not being
incremented with each attachment. The AttachmentPosition property indicates
the position of the attachment within the message. If two attachments
occupy the same position, an error occurs when the MAPIMessage's Send
method is called.