a strange problem,please help me!!

My .net is vs2003,the version of netframework is 1.1.4322

recently I began to program in intelligent device,using c# on pocket pc 2002 simulator.but file operations always have problems,for example:

private void button2_Click(object sender, System.EventArgs e)

{
StreamWriter SW;
SW=File.CreateText("c:\\shiyan.txt");
SW.WriteLine("123");
SW.WriteLine("345");
SW.Close();

}

unhandled exception： System.IO.DirectoryNotFoundException:

but this code run well in pure windows programs.Only in simulator can it have such problems.the file tpye of my harddisc is fat32.

another question is:

MessageBox.Show(this, "保存成功！", "tips",MessageBoxButtons.OK,MessageBoxIcon.Question, MessageBoxDefaultButton.Button1,MessageBoxOptions.RightAlign);

========
can't find type or namespace“MessageBoxOptions”(是否缺少 using 指令或程序集引用？)

how can this be possible what shall I do