Error using xlswrite；Error using javaMethod EDT

Hi,all

    My os is windows XP;
    When using xlswrite in a matlab executable file,I get an error message:
           Error using xlswrite;
           filename is empty;
           Error using javaMethod EDT;

   And datum can not be written into the excel file;
   But the second time use the xlswrite , the above error do not appear,and     datum can be imported to excel file;

Thank you for your help!