Error while package import

[momijigari]

When I import the "VFXToolbox" via Package Manager I recieve 1 warning and 3 errors. (and the import itself fails, as far as I understand)
Errors are:

**\VFXToolbox-master\Editor\ImageSequencer\ImageSequenceAssetEditor.cs(12,22): warning CS0414: The field 'ImageSequenceAssetEditor.m_PreviewOutput' is assigned but its value is never used

\VFXToolbox-master\Editor\ImageSequencer\ImageSequencer.Export.cs(195,46): error CS1061: 'TextureImporterSettings' does not contain a definition for 'flipbookRows' and no accessible extension method 'flipbookRows' accepting a first argument of type 'TextureImporterSettings' could be found (are you missing a using directive or an assembly reference?)

\VFXToolbox-master\Editor\ImageSequencer\ImageSequencer.Export.cs(194,46): error CS1061: 'TextureImporterSettings' does not contain a definition for 'flipbookColumns' and no accessible extension method 'flipbookColumns' accepting a first argument of type 'TextureImporterSettings' could be found (are you missing a using directive or an assembly reference?)

\VFXToolbox-master\Editor\ImageSequencer\ImageSequencer.Export.cs(193,82): error CS0117: 'TextureImporterShape' does not contain a definition for 'Texture2DArray'**