I can't find any clues at the link you have given.
I can see from the data received at the cffile upload script
that the data from Flex is correct and the same as the data
received from CF except that the form has two additional fields,
but these are not relevant as I have tried deleting them with
StructDelete and there is no difference.
The code in cffile upload is just:
<cffile action="upload" filefield="photo"
accept="image/jpeg, image/gif"
destination="D:inetpub\mysite\images" nameconflict="overwrite">
I think the problem must be with the destination which is why
I get an HTTPStatus Internal Server Error with upload from Flex.
With the CF input page, the file is saved correctly with the code
as shown.
From Flex, if I make other changes, I get different errors,
but it doesn't matter what nonsense I put in destination, I always
get this same HTTPStatus error.
The destination is a shared server and images folder has read
and write privileges for all users.
I just can't work out what can be wrong.
Doug