CDONTS Component Error

I have been using the CDONTS component on Windows 2000 to send emails for a
long time now (code below).
However, over time, the report that I am sending has got rather longer and
it now gives me an "unknown exception" error. However, I know that it's
because there's now too much data (If I remove some of the text it goes
fine).
I've "compacted" the message as much as I can, but I've got up to the limit
now of how much I can compact it by...
I've tried to write it to a file and attach that, but the same size limit
appears to hold for attachments too.
What to do....?