I've seen this same thing happen with people using OE to send me
other types of files.
A large fill is sent by him, it's split into 3-4 smaller files and
when it's received on my end it is Base64 encoded and is
lines and line long, still broken up and received in 3-4 email
The spliting seems to be done by OE or something on his computer that
splits the file into the smaller chunks.
We have tried to see what's happening , it must be something
in OE causing the spliting and encoding.
And you are right about sending it to another user using OE. Some
people get the file correctly in one file and others using OE just get
the parts with Base64 encoding.
If you find out the problem, post the answer,,
Robert Smith Consulting