Overview

When using the BulkImport module with the combination of PHP 8.1.29 and Omeka S version 4.0.4, the following error occurred.

Fatal error: Uncaught TypeError: mb_substr(): Argument #1 ($string) must be of type string, null given in /home/xxx/www/omeka-s/modules/BulkImport/src/Processor/ResourceProcessor.php:1079
Stack trace:
#0 /home/xxx/www/omeka-…

I have not been able to identify the root cause at this point, but I will describe the workaround.

Workaround

By using BulkImport v3.4.51 below, the above error no longer occurred.

Release BulkImport-3.4.51 · Daniel-KM/Omeka-S-module-BulkImport
Module for Omeka S that allows to create extensible importers and to process bulk import of any source (spreadsheet, another Omeka S…). - Release BulkImport-3.4.51 · Daniel-KM/Omeka-S-module-BulkImport
GitHub

Summary

I hope this is helpful.