Chapter 4. The RichFaces Migration Issues 3.1.x
Switching to JSF-RI 1.2_07 [https://javaserverfaces.dev.java.net/servlets/ProjectDocumentList? folderID=8467&expandFolder=8467&folderID=8819] fixes the problem (see forum post)
<rich:fileUpload> with Seam multi-part filter
The <rich:fileUpload> component does not work with Seam multi-part filter.
126.96.36.199. How to reproduce
The problem occurs if you use the <rich:fileUpload> component and Seam multi-part filter at the same time.
Lack of specification on the Servlet level does not allow to use stuff doing the same thing. One of them should be turned off.
The solution is turn the Seam multi-part filter off.