Help needed: "Setup failed: Value cannot be null. Parameter name: source"

I'm installing nopCommerce on AWS. My environment:
2 web servers (Win 2012 R2) behind Elastic Load Balancer
1 DataBase Server with SQL Server Installed
Redis Cache configured

Steps:
1) configured nopcommerce site in the IIS on the server 1 as a default site (127.0.0.1)
2) copied nopcommerce to a folder under wwwroot
3) enabled IIS_IUSRS modify access to the nopcommerce folder
4) configured web.config for distributed deployment:
    WebFarms MultipleInstancesEnabled="True" RunOnAzureWebsites="False"
    RedisCaching Enabled="true" ConnectionString="someroot.use1.cache.amazonaws.com:6379"
    sessionState mode="Custom" customProvider="MySessionStateStore"
      providers
        add name="MySessionStateStore" type="Microsoft.Web.Redis.RedisSessionStateProvider"
host="someroot.use1.cache.amazonaws.com:6379" accessKey="" ssl="true"
      providers
    sessionState
5) Run install on the server 1 (127.0.0.1/install)
6) Installation runs and after a while I get an error listed in the header. Data Base for nop  is created correctly as far as I see.

I would appreciate any pointers what am I doing wrong and what the next steps should be.

Best Regards,

I never made it to work. However you can still install nop on AWS using web farm env by installing as a non web farm app and then switching to web farm/redis config , then copying to every server (don't forget to generate machine keys and distribute it for every server)