Carrierwave - Can't upload multiple images

I am using jQuery File Upload http://blueimp.github.com/jQuery-File-Upload/

Together with Carrierwave for uploading images, with latest stable version of Ruby and Rails installed.

I managed to make it working by following this manual https://github.com/blueimp/jQuery-File-Upload/wiki/Rails-setup-for-V6

And it works perfectly well for uploading single images, but once I add HTML5 multiple attribute to allow uploading multiple images at once and select multiple images, I get following error on each request.

NoMethodError in Advertiser::MediaController#create undefined method `' for nil:NilClass

Every request seems absolutely same to me and I can't seem to figure out why it can't upload multiple images but can upload single images, please note that if I have multiple attribute enabled, I can't even upload a single image but once I take it off, uploading works once again. jQuery File Upload is perfectly capable of uploading multiple images and you can check it out in their demo.

Any hints on where to dig would be very much appreciated.

Thank you in advance.

The error message should tell you the line number so you can see where the problem is, you are calling on something that is nil. Have a look at the Rails Guide on Debugging to get ideas on how to debug the code.

Colin