On linux media type is prepended to ContentType causes failu

On linux machine the media type is prepended from message body to the Header ContentType. Where the same does not happen on Windows machine.
Due to this all our test cases are failing on linux environment. Can some one please help us to resolve this problem?

Hers is the scenario:

I am executing a HTTP Post request. In my request I have added two Header attributes i.e. Content-Type and MIME_version
and also I am also passing some value to request via message body.

On execution I see the following request being sent via SoapUI tool On linux machine

Note: Please see thh Content-Type value


Request from On Linux:
----------------- Properties ------------------------------
StatusCode: 200
Encoding:
Method: POST
Username:
HTTP Version: HTTP/1.1
Endpoint: https://SXXX.yahoo.com/rest/v1/d94
URL: https://SXXX.yahoo.com/rest/v1/d94

---------------- Request ---------------------------
MIME-Version: [1.0]
Host: [sxxx.yahoo.com]
Content-Length: [790]
Accept-Encoding: [gzip,deflate]
User-Agent: [Jakarta Commons-HttpClient/3.1]
Content-Type: [application/xml, multipart/form-data; boundary=----------Ij5Idjahdjhasjkdhasnjkdaskjd]



In case of windows I don't see any media type value being prepended to Content-Type

Request from windows:
POST https://Sxxx.yahoo.com/rest/v1/d94 HTTP/1.1
Accept-Encoding: gzip,deflate
MIME-Version: 1.0
Content-Type: multipart/form-data; boundary=----------Ij5Idjahdjhasjkdhasnjkdaskjd
User-Agent: Jakarta Commons-HttpClient/3.1
Host: sxxx.yahoo.com
Content-Length: 790

Can you please help me to resolve this issue?

Thanks