编译GWT应用程序时出现FileNotFoundException

Question

在编译我的GWT应用程序模块时，我收到此错误：

Linking into C:\workspace\MyGWT\war\user
   Linking Public artifacts into C:\workspace\MyGWT\war
      Emitting resource gwt/standard/images/corner.png
         [ERROR] Fatal error emitting this artifact
java.io.FileNotFoundException: C:\workspace\MyGWT\war\user\gwt\standard\images\corner.png (The system cannot find the path specified)
    at java.io.FileOutputStream.open(Native Method)
    at java.io.FileOutputStream.<init>(FileOutputStream.java:212)
    at java.io.FileOutputStream.<init>(FileOutputStream.java:165)

任何人都知道我为什么会遇到这种错误？