关于openlayers乱图的问题

.map文件为
MAP
EXTENT 70 5 140 55
IMAGETYPE png
SIZE 1000 800

OUTPUTFORMAT
NAME "png"
MIMETYPE "image/png"
DRIVER "GD/PNG"
EXTENSION "png"
IMAGEMODE "PC256"
TRANSPARENT TRUE
FORMATOPTION "INTERLACE=OFF"
END

QUERYMAP
COLOR 255 255 0
SIZE -1 -1
STATUS OFF
STYLE HILITE
END

WEB
IMAGEPATH "/"
IMAGEURL "/ms_tmp/"
METADATA
END
QUERYFORMAT text/html
END

LAYER
NAME 'bou2_4p'
TYPE POLYGON
EXTENT 49.189774-3.159989 173.282634 76.327090
DATA 'D:/project/test/bou2_4m/bou2_4p.shp'
METADATA
'wms_title' 'bou2_4p'
END
STATUS DEFAULT
TRANSPARENCY 20
PROJECTION
'proj=longlat'
'ellps=WGS84'
'datum=WGS84'
'no_defs'
END
CLASS
NAME 'bou2_4m'
STYLE
SYMBOL 0
SIZE 6
OUTLINECOLOR 255 130 120
COLOR 0 255 0
END
END
END

LAYER
NAME 'bou2_4l'
TYPE LINE
EXTENT 49.189774-3.159989 173.282634 76.327090
DATA 'D:/project/test/bou2_4m/bou2_4l.shp'
METADATA
'wms_title' 'bou2_4l'
END
STATUS DEFAULT
TRANSPARENCY 80
PROJECTION
'proj=longlat'
'ellps=WGS84'
'datum=WGS84'
'no_defs'
END
CLASS
NAME 'bou2_4l'
STYLE
SYMBOL 0
SIZE 36
OUTLINECOLOR 255 0 0
COLOR 0 0 250
END
END
END

END

.html为
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">

OpenLayer : Map Controls

#wrapper { width: 1000px; } #location { float: right; } #scale { float: left; } 

html, body { width: 100%; height: 100%; margin: 0; padding: 0; }

var map = null;
var wms_url = "http://192.168.0.129/cgi-bin/mapserv.exe?MAP=D:/installed/ms4w/Apache/htdocs/test.map";
var wms_layer0 = "bou2_4p";
var wms_layer1 = "bou2_4l"
var wms_format = 'image/png';

function init()
{
    //创建map对象，
    map = new OpenLayers.Map("map");
    var layer0 = new OpenLayers.Layer.WMS("layer0",
                                         wms_url,
                                         {
                                            layers    : wms_layer0, 
                                            format    : wms_format,
                                            singleTile: true,
                    Mode:'MAP'
                                         },
                     { isBaseLayer: true});

var layer1 = new OpenLayers.Layer.WMS("layer1",
                                         wms_url,
                                         {
                                            layers    : wms_layer1, 
                                            format    : wms_format,
                                            singleTile: true,
                    Mode:'MAP'
                                         },
                     { isBaseLayer: true});
    // 添加图层
    map.addLayers([layer0, layer1]);
map.numZoomLevels =13;  //设置缩放级别
//OpenLayers中默认加载的控件有4个:Navigation、Zoom、Attribution、ArgParser,地图初始化完成后，移除Zoom控件
var zoomControl = map.getControlsByClass('OpenLayers.Control.Zoom')[0];
map.removeControl(zoomControl); 
    // 添加Layer Switcher控件  图层切换  右上
    map.addControl( new OpenLayers.Control.LayerSwitcher());
    // 添加Mouse Position控件  显示鼠标所在位置坐标  正下
    map.addControl(new OpenLayers.Control.MousePosition({element: $('location')}));
    // 添加Map Scale控件
    map.addControl(new OpenLayers.Control.Scale($('scale')));
    // 添加PanZoomB 缩放控件  左上
map.addControl(new OpenLayers.Control.PanZoomBar());
    map.addControl(new OpenLayers.Control.Permalink());
//显示比例尺  左下
    map.addControl(new OpenLayers.Control.ScaleLine());
//显示鹰眼 右下
    map.addControl(new OpenLayers.Control.OverviewMap());
//显示经纬度
//map.addControl(new OpenLayers.Control.Graticule());
//添加绘制工具
//map.addControl(new OpenLayers.Control.EditingToolbar());
//添加导航控件
//map.addControl(new OpenLayers.Control.Navigation());                 

    // 放大到全屏
    map.zoomToMaxExtent();
}

结果图为：