My app works only on my PC
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I created this application in Windows Forms which is managing MySQL database by Entity Framework. I've published it and installed on my system and it worked fine... but when I've send it to my friend and he tried to run it, there is this error (sorry for my bad translation there]:

> System.TypeInitializationException: [type initiator prompted error for type] 'Kwestionariusz.Stuff.EntityManager'. ---> System.ArgumentException: [the supplier of the warehouse can't be found in the configuration or it isn't correct] ---> System.ArgumentException: [can't find wanted supplier of application data. it's possible that it's not installed].
    w System.Data.Common.DbProviderFactories.GetFactory(String providerInvariantName)
    w System.Data.EntityClient.EntityConnection.GetFactory(String providerString)

What they want me to install and why wasn't it installed by the installation of my software?