错误：Application not authorized to access the restricted API

[XSign]

程序有两个类文件SystemMainFrame为程序的主框架，也就是运行后显示的内容，部分内容如下

package src;


import javax.microedition.lcdui.Command;
…………
import src.QiangZhiXianForm;

public class SystemMainFrame extends MIDlet implements CommandListener{
	…………
	private QiangZhiXianForm qiangZhiXian;//改成private Form qiangZhiXian出现同样的错误

	protected void startApp() throws MIDletStateChangeException {
		if (mainScr == null) {
		      …………		      
		      mainScr.setCommandListener(this);
		    }
		    display.setCurrent(mainScr);	

	}
	
	  public void commandAction(Command c, Displayable d) {
		    if (d == mainScr) {
		      // Handle main sceen
		      if (c == cmdExit) {
		    	  
		      } else if ((c == List.SELECT_COMMAND) || (c == cmdSelect)) {
		        switch (mainScr.getSelectedIndex()) {
		        case 0:
		        genQiangZhiXian(); //调用函数，完成界面的更新！调用这个函数报错！！
		          break;
		        case 1:
		         
		          break;
		        case 2:
		          
		          break;
		        case 3:
		          
		          break;
		        default:
		          
		        }
		      }
		    } 
		  }
	  	  
	  private Screen genQiangZhiXian()//调用这个函数报错！！
	  {		  
		  qiangZhiXian = new QiangZhiXianForm("交通事故责任强制保险");
                  display.setCurrent(qiangZhiXian);
		  		  
		  return qiangZhiXian;
	  }
}

QiangZhiXianForm类为一个字功能的界面类，为了方便程序的维护，我想把它写在一个类中。以下是完整代码：

package src;

import javax.microedition.lcdui.Command;
import javax.microedition.lcdui.Form;
import javax.microedition.lcdui.Item;
import javax.microedition.lcdui.TextField;

public class QiangZhiXianForm extends Form {
	private TextField txtFieldUsedYear;
	private TextField txtFieldGl;
	private TextField txtFieldSiteNum;
	private TextField txtFieldZzl;
	
	private Command cmdOk;
	private Command cmdBack;
	

	public QiangZhiXianForm(String title) {
		super(title);
		
		txtFieldUsedYear = new TextField("已使用年限","",3,TextField.NUMERIC);
		txtFieldGl = new TextField("排气量/功率（C.C./KW）","",5,TextField.NUMERIC);
		txtFieldSiteNum = new TextField("座位数（包括司机）","",3,TextField.NUMERIC);
		txtFieldZzl = new TextField("核定载重量（吨）","",4,TextField.NUMERIC);
		
		cmdOk = new Command("OK",Command.OK,1);
		cmdBack = new Command("Back",Command.BACK,2);	
		
		this.append(txtFieldUsedYear);
		this.append(txtFieldGl);
		this.append(txtFieldSiteNum);
		this.append(txtFieldZzl);
		
		this.addCommand(cmdOk);
		this.addCommand(cmdBack);
		
		this.setCommandListener(new SystemMainFrame());
	}

	public QiangZhiXianForm(String arg0, Item[] arg1) {
		super(arg0, arg1);
		// TODO Auto-generated constructor stub
	}

}

现在程序报错:
Running with storage root DefaultGrayPhone
Running with locale: Chinese_People's Republic of China.936
java.lang.SecurityException: Application not authorized to access the restricted API
at com.sun.midp.security.SecurityToken.checkIfPermissionAllowed(+40)
at com.sun.midp.security.SecurityToken.checkIfPermissionAllowed(+7)
at com.sun.midp.midletsuite.MIDletSuiteImpl.checkIfPermissionAllowed(+8)
at com.sun.midp.midlet.MIDletState.<init>(+83)
at javax.microedition.midlet.MIDletProxy.<init>(+5)
at javax.microedition.midlet.MIDlet.<init>(+13)
at src.SystemMainFrame.<init>(+4)
at src.QiangZhiXianForm.<init>(+163)
at src.SystemMainFrame.genQiangZhiXian(+10)
at src.SystemMainFrame.commandAction(+72)
at javax.microedition.lcdui.Display$DisplayAccessor.commandAction(+282)
at javax.microedition.lcdui.Display$DisplayManagerImpl.commandAction(+10)
at com.sun.midp.lcdui.DefaultEventHandler.commandEvent(+68)
at com.sun.midp.lcdui.AutomatedEventHandler.commandEvent(+47)
at com.sun.midp.lcdui.DefaultEventHandler$QueuedEventHandler.handleVmEvent(+194)
at com.sun.midp.lcdui.DefaultEventHandler$QueuedEventHandler.run(+51)
Execution completed.
3423739 bytecodes executed
472 thread switches
1647 classes in the system (including system classes)
17960 dynamic objects allocated (545276 bytes)
3 garbage collections (463880 bytes collected)

貌似是调用了受限制的API函数，请问如何解决这个问题？