HOw can I upload a txt file from wml page to my server

I created some wml pages with jsp, now I need a method to upload some files(such as txt file) from wap phone/pda to server,
I tried Jakarta FileUpload1.0.

on client side, my code like following :

File :<input type="file" name="hwupload" size="40" ><br/>

<do type="accept" label="Upload">

<go href="save.jsp" method="post" ENCTYPE="multipart/form-data">
<postfield name="uploadhw" value="$(hwupload)"/>

</go>
</do>

The sever error msg like following:

The server encountered an internal error () that prevented it from fulfilling this request.</u></p><p><b>exception</b> <pre>org.apache.jasper.JasperException: the request doesn't contain a multipart/form-data or multipart/mixed stream, content type header is application/x-www-form-urlencoded


Thank you so much for any idea!

Ray