If I desactivate the line that controls if the table name is longer than 28 chars moodle shows this error:

Strict Standards: Declaration of plagiarism_plugin_crot::get_form_elements_module() should be compatible with that of plagiarism_plugin::get_form_elements_module() in /codigoCentros/mdl_crot/plagiarism/crot/lib.php on line 37

Result: moodle can't save setting of crot.