trf causes mailing failure in smtp module

I been creating a mass mailing program using TCL/TK.
This necessitates the use of the mime and smtp
packages. Initially everything seemed fine until I
tried to send a file larger than 10KB. I would then
get a socket error so I discussed this with Pat
Thoyts and he told me to try using sockspy to observe
what was happening. I did and my emails sent just
fine while passing through sockspy. I was quite
baffled and so was he so he suggested using the
iocpsock socket package. I did and it seemed to be
working for the emails that I was trying to send at
that time so I thought the issue was resolved. Now I
am trying to send large attachments and am right back
where I was before. So, I spent about 2 days going
through the smtp.tcl file trying to understand how it
was different from sockspy. I finally narrowed it
down to this trf package. When I remove this package
from the smtp module my emails send just fine, no
errors at all. I have a feeling this is also related
to my platform in some way. I'm running Windows XP
Pro. I have not tried running it on Windows 2000 so
I'm not sure about this, although Pat seemed to think
that he could send some large files using the same
code on his machines:

"I have XP Home here now but XP Pro at work and I've
send messages using tcl with both operating systems
so I don't believe there is a problem there." - Pat

He also suggested that an AV program might be
interfering with the smtp function so I shutdown my
firewalls and my AV stuff and nothing seemed to
improve this.

I hope you will have enough to information to move
forward here. The problem is definitely related
either to trf or to something underlying it.

Thanks for checking into it.

Robert Joy