I uploaded a batch of images using Filezilla to 123RF. When I try to process them using the upload function in their website, it cannot detect any of the uploaded files. So many problems with this site.. 

Is it working for everyone else?

I get the same.
Seems the files don't get moved from the FTP.

seems to work for me

Works here too again. It just took a very long time from upload till they showed up in the queue.

In the mean time I uploaded my files via the web-form, and then I suddely had them twice 

Have they automated FTP processing? My files have directly gone to 'Manage Media'.