PCSDK 6.05. BACKUP-Error

Hello,
I was creating an PC-SDK-Application and getting some troubles with RW 6.04.01 on
the real robot system.

I have also troubles creating a BACKUP of the system - VC is working and real system is creating errors.
The robot system is creating a BACKUP-Error - Error-ID: 11020.

My source code:
private void saveFileDialog1_FileOk(object sender, CancelEventArgs e)
{
if (controllerLokal != null || saveFileDialog1.FileName.ToString() != “” || saveFileDialog1.FileName != null)
{
try
{
string backupDir = saveFileDialog1.FileName.ToString();
this.controllerLokal.BackupCompleted += new EventHandler(Controller_BackupCompleted);
this.controllerLokal.Backup(backupDir);
}
catch
{
ShowMessage(translator.getText(“Backupfehler”));
}
}
else
{

}
}

I would be appreciated for help
Thank you in advance