"I am trying to upload multiple files.  The first file uploads all the way to 100%, but the next file never starts to upload.  I can't upload more than one file."

This is most often due to an outdated version of Adobe Flash, and can be easily fixed.  To make sure you have the most recent version of Adobe Flash, do the following:

1. go to http://www.adobe.com/software/flash/about/
2. in a gray square on this site, in the middle and slightly to the right on your screen, you will see something that says "Version Information."  Below this, you will see a table that lists what flash version you need to have according to which operating system you are using (Windows, Mac OSX, etc)
3. If you do not have the most recent flash version, you will need to install it.  To do this, go to: http://get.adobe.com/flashplayer/otherversions/   and install the new version of flash for your operating system.
4. Once your flash has been installed, your upload should proceed normally.