Rails - May 2006 - POST op parameters are coming in as StringIOs

I''m receiving a multipart post request from another server.  The  
request parameters are being received as StringIOs, rather than plain  
strings.   For instance :

Processing MessagesController#receive (for 83.166.68.31 at 2006-05-24  
10:36:53) [POST]
   Session ID: eedafb24033be0714f8133f02810083f
   Parameters: {"message"=>#<StringIO:0xb7503358>,
"date"=>#<StringIO:
0xb7501f30>, "from"=>#<StringIO:0xb7502944>,
"type"=>#<StringIO:
0xb7503d6c>, "action"=>"receive",
"id"=>#<StringIO:0xb750151c>,
"to"=>#<StringIO:0xb75047bc>,
"controller"=>"messages"}


If I try to get the actual parameter with (for instance) params 
[:message].read, it works as expected...but surely this shouldn''t be  
necessary?



Any idea why this is happening?  I''m out of ideas...any help would be  
massively appreciated.

Jon