Newbie file download question

Hi to everyone on the list. I’m a newbie to ruby on rails but so far i’m
liking every second of development with it.
That said, i have a minor problem using the send_file method.

My application takes an uploaded file and writes it to the file system,
then
i run some ruby code to parse the file and convert it to xml. All of
this
runs without a problem. However, when i try to push the file for the
user to
download, i get the following error:

IndexError in File#download
index 543879 out of string

here is the trace
/usr/lib/ruby/gems/1.8/gems/actionpack-1.11.0/lib/action_controller/streaming.rb:57:in
[]=' /usr/lib/ruby/gems/1.8/gems/actionpack-1.11.0/lib/action_controller/streaming.rb:57:insend_file’
#{RAILS_ROOT}/app/controllers/file_controller.rb:12:in `download’

right now the files reside in a directory i created called work, but i
get
the same error when i put the files into the public directory

does anybody have any suggestions?

Thanks in advance for the help

Chris M.