setReport throws error

Hi, i am using getReport to modify it later and re set it with the modified report. Note that I am using analysis service data source.
But i noticed that when i put a row field and if i use getreport and setreport with the exact same report i previously got from getreport, it throws me the following error: "Cannot read property 'hierarchy' of undefined".
If i don't use the getReport and set setReport code part it works perfectly fine. It really is when i set the report like the following:
var report = $scope.pivot.getReport();
$scope.pivot.setReport(report);
it throws the error i mentioned.. I don't understand why. my report object seems totally fine.
Edit: Actually, there is alot of errors with flexmonster when you set the report with setReport method even tho the report object is the one generated by the getReport method... When you set the report with the very same report you get from getReport, the code breaks from everywhere...