QFormBuilder load and save

QFile file(settings.value("/Settings/pathForm","").toString()+"/"+filename);
QFormBuilder loader;
file.open(QFile::ReadOnly);
QWidget *formWidget = loader.load(&file, this);

QFormBuilder builder;
QFile file1("c:\myWidget.ui");
file1.open(QFile::WriteOnly);
builder.save(&file1,formWidget);
file1.close();
file.close();

Reading ui file, which was build in Designer.
After copy procedure, I have a file myWidget.ui.
When I try open this file in Designer, Designer crashed up.

Both ui files in zip.
Sorry for my English