You have to patch Sitecore config \App_Config\Include\Y.Commerce.Engine\Sitecore.Commerce.Engine.TemplateGenerator.config
<configuration xmlns:patch="http://www.sitecore.net/xmlconfig/" xmlns:role="http://www.sitecore.net/xmlconfig/role/">
<sitecore role:require="Standalone or ...
It seems PriceBookToCatalog relationship definition is missing. This is often an indication that the environment was not initialized properly. Try to reinitialize the environment and make sure the relationship definitions are