wr_10은 null 이거나 개체가 아닙니다.
오류메시지 줄은

write.php에서
2개 셀렉트 문이 나란히 있습니다.
첫번째, 지역을 선택하면, 두 번째는 한식이나 중식, 양식 등을 선택합니다.

wr_10 에는 한식^중식^일식^부페^기타를 선택 할 수 있습니다.
게시판 분류에 서울|대구|대전 등 지역분류가 사용가능합니다.
맛집게시판 db wr_9 에는 한식이나 중식 등이 들어갑니다.

첫번째, 지역을 선택하면, 아래 에러가 나옵니다. 두번째 선택도 아래 에러가 나옵니다.

wr_10은 null 이거나 개체가 아닙니다. wr_10 필드는 한식이나 중식 등 이 들어 있습니다.(한식, 중식, 양식 등)

--------------------------------------------
<script language="javascript">

function Category(value) {
  this.value = value;
  this.length = 0;
}

function addCategory(category, value) {
  category[category.length] = new Category(value);
  category.length++;
}

var category = new Category();

addCategory(category, '0');
addCategory(category[0],':: 선택하세요 ::');
addCategory(category[0][0],':: 선택하세요 ::');


addCategory(category, '1');addCategory(category[1],'한식');addCategory(category[1][0], '');addCategory(category[1],'중식');addCategory(category[1][1], '');addCategory(category[1],'일식');addCategory(category[1][2], '');addCategory(category[1],'부페');addCategory(category[1][3], '');addCategory(category[1],'기타');addCategory(category[1][4], '');addCategory(category, '2');addCategory(category[2],'한식');addCategory(category[2][0], '');addCategory(category[2],'중식');addCategory(category[2][1], '');addCategory(category[2],'일식');addCategory(category[2][2], '');addCategory(category[2],'부페');addCategory(category[2][3], '');addCategory(category[2],'기타');addCategory(category[2][4], '');addCategory(category, '3');addCategory(category[3],'한식');addCategory(category[3][0], '');addCategory(category[3],'중식');addCategory(category[3][1], '');addCategory(category[3],'일식');addCategory(category[3][2], '');addCategory(category[3],'부페');addCategory(category[3][3], '');addCategory(category[3],'기타');addCategory(category[3][4], '');addCategory(category, '4');addCategory(category[4],'한식');addCategory(category[4][0], '');addCategory(category[4],'중식');addCategory(category[4][1], '');addCategory(category[4],'일식');addCategory(category[4][2], '');addCategory(category[4],'부페');addCategory(category[4][3], '');addCategory(category[4],'기타');addCategory(category[4][4], '');addCategory(category, '5');addCategory(category[5],'한식');addCategory(category[5][0], '');addCategory(category[5],'중식');addCategory(category[5][1], '');addCategory(category[5],'일식');addCategory(category[5][2], '');addCategory(category[5],'부페');addCategory(category[5][3], '');addCategory(category[5],'기타');addCategory(category[5][4], '');addCategory(category, '6');addCategory(category[6],'한식');addCategory(category[6][0], '');addCategory(category[6],'중식');addCategory(category[6][1], '');addCategory(category[6],'일식');addCategory(category[6][2], '');addCategory(category[6],'부페');addCategory(category[6][3], '');addCategory(category[6],'기타');addCategory(category[6][4], '');addCategory(category, '7');addCategory(category[7],'한식');addCategory(category[7][0], '');addCategory(category[7],'중식');addCategory(category[7][1], '');addCategory(category[7],'일식');addCategory(category[7][2], '');addCategory(category[7],'부페');addCategory(category[7][3], '');addCategory(category[7],'기타');addCategory(category[7][4], '');addCategory(category, '8');addCategory(category[8],'한식');addCategory(category[8][0], '');addCategory(category[8],'중식');addCategory(category[8][1], '');addCategory(category[8],'일식');addCategory(category[8][2], '');addCategory(category[8],'부페');addCategory(category[8][3], '');addCategory(category[8],'기타');addCategory(category[8][4], '');addCategory(category, '9');addCategory(category[9],'한식');addCategory(category[9][0], '');addCategory(category[9],'중식');addCategory(category[9][1], '');addCategory(category[9],'일식');addCategory(category[9][2], '');addCategory(category[9],'부페');addCategory(category[9][3], '');addCategory(category[9],'기타');addCategory(category[9][4], '');addCategory(category, '10');addCategory(category[10],'한식');addCategory(category[10][0], '');addCategory(category[10],'중식');addCategory(category[10][1], '');addCategory(category[10],'일식');addCategory(category[10][2], '');addCategory(category[10],'부페');addCategory(category[10][3], '');addCategory(category[10],'기타');addCategory(category[10][4], '');addCategory(category, '11');addCategory(category[11],'한식');addCategory(category[11][0], '');addCategory(category[11],'중식');addCategory(category[11][1], '');addCategory(category[11],'일식');addCategory(category[11][2], '');addCategory(category[11],'부페');addCategory(category[11][3], '');addCategory(category[11],'기타');addCategory(category[11][4], '');addCategory(category, '12');addCategory(category[12],'한식');addCategory(category[12][0], '');addCategory(category[12],'중식');addCategory(category[12][1], '');addCategory(category[12],'일식');addCategory(category[12][2], '');addCategory(category[12],'부페');addCategory(category[12][3], '');addCategory(category[12],'기타');addCategory(category[12][4], '');addCategory(category, '13');addCategory(category[13],'한식');addCategory(category[13][0], '');addCategory(category[13],'중식');addCategory(category[13][1], '');addCategory(category[13],'일식');addCategory(category[13][2], '');addCategory(category[13],'부페');addCategory(category[13][3], '');addCategory(category[13],'기타');addCategory(category[13][4], '');addCategory(category, '14');addCategory(category[14],'한식');addCategory(category[14][0], '');addCategory(category[14],'중식');addCategory(category[14][1], '');addCategory(category[14],'일식');addCategory(category[14][2], '');addCategory(category[14],'부페');addCategory(category[14][3], '');addCategory(category[14],'기타');addCategory(category[14][4], '');addCategory(category, '15');addCategory(category[15],'한식');addCategory(category[15][0], '');addCategory(category[15],'중식');addCategory(category[15][1], '');addCategory(category[15],'일식');addCategory(category[15][2], '');addCategory(category[15],'부페');addCategory(category[15][3], '');addCategory(category[15],'기타');addCategory(category[15][4], '');addCategory(category, '16');addCategory(category[16],'한식');addCategory(category[16][0], '');addCategory(category[16],'중식');addCategory(category[16][1], '');addCategory(category[16],'일식');addCategory(category[16][2], '');addCategory(category[16],'부페');addCategory(category[16][3], '');addCategory(category[16],'기타');addCategory(category[16][4], '');
function initForm(form) {
  form.ca_name_a.length = category.length;
  for (i = 0; i < category.length; i++)
    form.ca_name_a[i].text = category[i].value;
  form.ca_name_a.selectedIndex = 0;
  form.wr_9.selectedIndex = 0;
  change_ca_name_a(form);
}

function change_ca_name_a(form) {
  var i = form.ca_name_a.selectedIndex;
  form.wr_9.length = category[i].length;
  for (j = 0; j < form.wr_9.length; j++)
    form.wr_9[j].text = category[i][j].value;
  form.wr_9.selectedIndex = 0;
  change_wr_9(form);
}

function change_wr_9(form) {
  var i = form.ca_name_a.selectedIndex
  var j = form.wr_9.selectedIndex;
  form.wr_10.length = category[i][j].length; *************************** 에러부분입니다.
  for (k = 0; k < form.wr_10.length; k++)
    form.wr_10[k].text = category[i][j][k].value;
  form.wr_10.selectedIndex = 0;
}

// -->
</SCRIPT>

---------------------------------------
write.php

<? if ($is_category) { ?>
<tr>
    <td class=write_head>지 역</td>
    <td><select name=ca_name required itemname="분류" onChange="change_ca_name(this.form)">
      <option>:: 선택하세요 ::</option>
      <?=$categorys?>
    </select>
    <select class="ed" name="wr_9" onChange="change_wr_9(this.form)"><? if($wr_9s){echo $wr_9s;}else{echo "<option>:: 선택하세요 ::</option>";};?></select> </td>
</tr>
-------------------------------------------------------------
ca_name을 다른 스킨에서 사용해서, 혹시나 해서 ca_name_a로 바꾸어도 보았어요. (상관없음) ㅠ.ㅠ

그누 최신버전으로 설치하고, 예전스킨을 업로드 하였는데, ,, 이런 에러가 나네요..
????????????