Multiple scripts Errors on importing Chronos in Unity 2019.4

We just imported for the first time the Chronos package into our game using Package Manager and got the following errors in the console:

Assets\Ludiq\Ludiq.Chronos\Source\Editor\ClockEditor.cs(8,29): error CS0118: 'Editor' is a namespace but is used like a type

Assets\Ludiq\Ludiq.Chronos\Source\Editor\CustomRecorderEditor.cs(8,38): error CS0118: 'Editor' is a namespace but is used like a type

Assets\Ludiq\Ludiq.Chronos\Source\Editor\ClockEditor.cs(23,24): error CS0115: 'ClockEditor.OnInspectorGUI()': no suitable method found to override

Assets\Ludiq\Ludiq.Chronos\Source\Editor\CustomRecorderEditor.cs(17,24): error CS0115: 'CustomRecorderEditor.OnInspectorGUI()': no suitable method found to override

Assets\Ludiq\Ludiq.Chronos\Source\Editor\TimekeeperEditor.cs(9,34): error CS0118: 'Editor' is a namespace but is used like a type

Assets\Ludiq\Ludiq.Chronos\Source\Editor\TimelineChildEditor.cs(8,37): error CS0118: 'Editor' is a namespace but is used like a type

Assets\Ludiq\Ludiq.Chronos\Source\Editor\TimelineEditor.cs(8,32): error CS0118: 'Editor' is a namespace but is used like a type

Assets\Ludiq\Ludiq.Chronos\Source\Editor\TimelineChildEditor.cs(17,24): error CS0115: 'TimelineChildEditor.OnInspectorGUI()': no suitable method found to override

Assets\Ludiq\Ludiq.Chronos\Source\Editor\TimekeeperEditor.cs(20,24): error CS0115: 'TimekeeperEditor.OnInspectorGUI()': no suitable method found to override

Assets\Ludiq\Ludiq.Chronos\Source\Editor\TimelineEditor.cs(25,24): error CS0115: 'TimelineEditor.OnInspectorGUI()': no suitable method found to override

We're using Chronos version 2.4.15 with Unity LTS 2019.4.10f1. The project structure is shown in the following screenshot:

Also, in case that is matter, we're not using any other external packages in our project.

Please take a look and inform us for potential solutions.