分析错误:语法错误，意外的T_VARIABLE，在PHP 5.3中应为T_STRING

我有问题。。。上面写着"出乎意料的T_VARIABLE"。有问题的线路是：

$children[ $i['parent_id'] ][] = array($i['forum_id'], "<option value='"{$i['forum_id']}'"$selected>  ", "{$i['forum_name']}</option>'n");

我尝试删除$（在$children中），但它仍然导致错误。上面写着"分析错误：语法错误，在中意外的‘[’"

奇怪的是，这在PHP 5.2中可以正常工作。但在PHP 5.3中，问题出现了。

由于我不是一个真正的程序员（只知道一点基础知识，我主要是设计），我对这里发生的事情真的一无所知。有人能帮忙吗？

以下是完整的功能：

function build_forum_jump($html=1, $override=0, $remove_redirects=0)
{
    global $INFO, $DB, $ibforums;
    $last_cat_id = -1;
    if ( $remove_redirects )
    {
        $qe = 'AND f.redirect_on <> 1';
    }
    else
    {
        $qe = '';
    }
    $DB->query("SELECT f.id as forum_id, f.parent_id, f.subwrap, f.sub_can_post, f.name as forum_name, f.position, f.redirect_on, f.read_perms, c.id as cat_id, c.name
                FROM ibf_forums f
                 LEFT JOIN ibf_categories c ON (c.id=f.category)
                WHERE c.state IN (1,2) $qe
                ORDER BY c.position, f.position");

    if ($html == 1) {
        $the_html = "<form onsubmit='"if(document.jumpmenu.f.value == -1){return false;}'" action='{$ibforums->base_url}act=SF' method='get' name='jumpmenu'>
                     <input type='hidden' name='act' value='SF' />'n<input type='hidden' name='s' value='{$ibforums->session_id}' />
                     <select name='f' onchange='"if(this.options[this.selectedIndex].value != -1){ document.jumpmenu.submit() }'" class='forminput'>
                     <optgroup label='"{$ibforums->lang['sj_title']}'">
                      <option value='sj_home'>{$ibforums->lang['sj_home']}</option>
                      <option value='sj_search'>{$ibforums->lang['sj_search']}</option>
                      <option value='sj_help'>{$ibforums->lang['sj_help']}</option>
                     </optgroup>
                     <optgroup label='"{$ibforums->lang['forum_jump']}'">";
    }
    $forum_keys = array();
    $cat_keys   = array();
    $children   = array();
    $subs       = array();
    $subwrap    = array();
    // disable short mode if we're compiling a mod form
    if ($html == 0 or $override == 1)
    {
        $ibforums->vars['short_forum_jump'] = 0;
    }
    while ( $i = $DB->fetch_row() )
    {
        $selected = '';
        $redirect = "";
        if ($html == 1 or $override == 1)
        {
            if ($ibforums->input['f'] and $ibforums->input['f'] == $i['forum_id'])
            {
                $selected = ' selected="selected"';
            }
        }
        if ( $i['redirect_on'] )
        {
            $redirect = $ibforums->lang['fj_redirect'];
        }
        if ($i['subwrap'] == 1)
        {
            $subwrap[ $i['forum_id'] ] = 1;
        }
        if ($i['subwrap'] == 1 and $i['sub_can_post'] != 1)
        {
        /***************************
        *** INFINITE SUBFORUMS 
        ****************************/
        if ($i['parent_id'] > 0)    {
            $children[ $i['parent_id'] ][] = array($i['forum_id'], "<option value='"{$i['forum_id']}'"".$sub_css."$selected>  ", "{$i['forum_name']}$is_sub</option>'n");
        }
        else    {
            $forum_keys[ $i['cat_id'] ][$i['forum_id']] = "<option value='"{$i['forum_id']}'"".$sub_css."$selected>  -{$i['forum_name']}$is_sub</option>'n";
        }
        /**********INFINITE - END**************/
        }
        else
        {
            if ( $this->check_perms($i['read_perms']) == TRUE )
            {
                if ($i['parent_id'] > 0)
                {
                /***************************
                *** INFINITE SUBFORUMS
                ****************************/
                $children[ $i['parent_id'] ][] = array($i['forum_id'], "<option value='"{$i['forum_id']}'"$selected>  ", "{$i['forum_name']}</option>'n");
                /**********INFINITE - END**************/
                }
                else
                {
                    $forum_keys[ $i['cat_id'] ][$i['forum_id']] = "<option value='"{$i['forum_id']}'"".$selected.">&nbsp;&nbsp;- {$i['forum_name']} $redirect</option><!--fx:{$i['forum_id']}-->'n";
                }
            }
            else
            {
                continue;
            }
        }
        if ($last_cat_id != $i['cat_id'])
        {
            // Make sure cats with hidden forums are not shown in forum jump
            $cat_keys[ $i['cat_id'] ] = "<option value='-1'>{$i['name']}</option>'n";
            $last_cat_id = $i['cat_id'];
        }
    }
    foreach($cat_keys as $cat_id => $cat_text)
    {
        if ( is_array( $forum_keys[$cat_id] ) && count( $forum_keys[$cat_id] ) > 0 )
        {
            $the_html .= $cat_text;
            foreach($forum_keys[$cat_id] as $idx => $forum_text)
            {
                if ( $subwrap[$idx] != 1 )
                {
                    $the_html .= $forum_text;
                }
                else if (count($children[$idx]) > 0)
                {
                    $the_html .= $forum_text;
                    if ($ibforums->vars['short_forum_jump'] != 1)
                    {
                        /****** INFINITE SUBFORUMS FIX BEGINS ************/
                        $the_html .= $this->subforums_addtoform($idx, '$children);
                        /********** INFINITE FIX - END ************/
                    }
                    else
                    {
                        $the_html = str_replace( "</option><!--fx:$idx-->", " (+".count($children[$idx])." {$ibforums->lang['fj_subforums']})</option>", $the_html );
                    }
                }
                else
                {
                    $the_html .= $forum_text;
                }
            }
        }
    }

    if ($html == 1)
    {
        $the_html .= "</optgroup>'n</select>&nbsp;<input type='submit' value='{$ibforums->lang['jmp_go']}' class='forminput' /></form>";
    }
    return $the_html;
}