异常？速救！！！

[caiyun]

OpenDialog1.Title:='打开工程项目';
if OpenDialog1.Execute then
begin
//设置连接字符串
DataBaseName:=OpenDialog1.FileName;//数据库名扩展名是（*.mdb)ado连接
ConnectStr:='Provider=Microsoft.Jet.OLEDB.4.0;Data Source='+DataBaseName+';';
ProjectDatamodule.ProjectConnection.ConnectionString:=ConnectStr+'Persist Security Info=true';
ProjectDatamodule.ProjectConnection.Connected:=true;
try
Projectdatamodule.properquery.Open;
//设置主窗体的标题
ProjectName:=trim(Projectdatamodule.properquery.Fieldbyname('jsxmmc').value);
MainForm.Caption:='安装工程套价系统...['+ProjectName+']';
//设置项目工具栏
ToolButton5.Enabled:=true;
ToolButton6.Enabled:=true;
ToolButton7.Enabled:=true;
ToolButton8.Enabled:=true;
ToolButton12.Enabled:=true;
n2.Enabled:=true;
n3.Enabled:=true;
n4.Enabled:=true;
n5.Enabled:=true;
n15.Enabled:=true;
ToolButton3.Enabled:=false;
ToolButton4.Enabled:=false;
n7.Enabled:=false;
n8.Enabled:=false;
except
on E: error do
application.MessageBox('项目工程不完整！','提示',mb_ok+mb_iconinformation);
end;
projectdatamodule是数据模块，properquery是query控件(select * from jsxm)
打开的文件不存在这个表！处发异常怎么做？