Did you find a fix for this? I'm having the same issue. The portlet works fine using just uPortal; however, when using the same exact code in Luminis IV it doesn't seem to send any information over. Other forms work fine, so my guess is that it has to do with the multipart/form-data mime-type. I posted this issue to the lumdev forum and am going to open up a support ticket for it soon.
Joined: Jul 05, 2011
I implemented a workaround and am just using commons-upload in a servlet now.