Built-in assets should not show errors. But because of the different way the assets are stored the assets can show errors if they have been opened for edit and then committed or if a database repair has been carried out and has thrown up false errors.
To sort out the first instance you need to revert the asset to original (under the edit menu). The second one can be corrected by right clicking on the asset and viewing errors, it should show no errors and the asset will then not show the red warning icon.