Hi,
I have compiled the version against v3.40 and sent you source code again. Since you updated some reference already it might happen that it will not run. Do not upgrade to latest nuget packages since some code will not run and you will need to update the source code. If you can you do a clean install of v3.40 again and put the compiled version there in the presentation->nop.framework->plugins folder. You can keep the same database. Take care of your web.config and files in the app_data folder. You need to keep those.
Other way around is to update the reference through nuget manager on the project.. Remove all of them and then go to the solution.right click there and click manage. then add the same references as for Froogle plugin. This plugin is basically and enhanced version of it.
J.