Some of the IDs in the specified spatial weights matrix file are not unique, indicating the format of this file is not correct.
Check the spatial weights matrix file format. Alternatively, re-create the spatial weights matrix file using the Generate Spatial Weights Matrix tool. This tool will require a unique ID field. If your feature class does not have a unique ID field, it can be created by using AddField to create a new field in the feature class, then using Calculate Field to set the values of the new field equal to the FID/OID field.