Sometimes if you have MaxPostSize set in Apache configuration(httpd.conf) to lower number such as 2048 bytes, you may get into error 413 when you perform operations such as file upload, data transfer from the browser. I had this issue for some of my applications deployed in weblogic server 10.3 with Apache proxying the requests.
You might want either increase the size or remove it completely. if you don't mention it will take default integer which is -1. this means unlimited size.
If you would like to know how to integrate Apache with Weblogic, please visit this blog.