Error posting data to index.php of wordpress Thema

Question

Hello I am getting a Error of the Wordpress includes, this error appears when I post the multiple values of a taxonomy to index.php

<form role="search" method="post" id="searchform" action="<?php echo home_url( '/' ); ?>">

<select name="books[]" multiple>
  <option value="a">a</option>
  <option value="b">b</option>
</select>
<input type="submit" id="searchsubmit" value="Search" />
</form>

Warning: strpos() expects parameter 1 to be string, array given in www.domain.com\wordpress\wp-includes\query.php on line 1718

Warning: preg_split() expects parameter 2 to be string, array given in www.domain.com\wordpress\wp-includes\query.php on line 1719

Warning: Invalid argument supplied for foreach() in www.domain.com\wordpress\wp-includes\query.php on line 1720

    foreach ( $GLOBALS['wp_taxonomies'] as $taxonomy => $t ) {
        if ( 'post_tag' == $taxonomy )
            continue;   // Handled further down in the $q['tag'] block

        if ( $t->query_var && !empty( $q[$t->query_var] ) ) {
            $tax_query_defaults = array(
                'taxonomy' => $taxonomy,
                'field' => 'slug',
            );

            if ( isset( $t->rewrite['hierarchical'] ) && $t->rewrite['hierarchical'] ) {
                $q[$t->query_var] = wp_basename( $q[$t->query_var] );
            }

            $term = $q[$t->query_var];

            if ( strpos($term, '+') !== false ) {
                $terms = preg_split( '/[+]+/', $term );
                foreach ( $terms as $term ) {
                    $tax_query[] = array_merge( $tax_query_defaults, array(
                        'terms' => array( $term )
                    ) );
                }
            } else {
                $tax_query[] = array_merge( $tax_query_defaults, array(
                    'terms' => preg_split( '/[,]+/', $term )
                ) );
            }
        }
    }

The error does not appear when I post it to searchresults.php or when I use when I use a single value or a none taxonomy name;

<select name="books">
<select name="NoneTaxonomyName[]" multiple>

does someone know how to resolve this?

Answer 1

solved with; query_var => false

register_taxonomy('taxname', 'post_type', array('hierarchical' => true, 'label' => 'lable',     'query_var' => false, 'rewrite' => array('slug' => 'slug')));