Just tested the flatfile importer module on Mx 5.19. You'll need to update the layouts to the new navigation layouts, until a new version is released. The module functions correctly and allows importing the data as described for the module. So I'm not sure what the error is you are getting, but the module seems to work fine (even in 6.1 as Dennis stated in the comment)
I have updated the layouts, But the flat file exporter in my system is not working for 5.19 and because it is using replication.jar, I am getting the following error in java method 'GetValueFromReference' ,"Value = ValueParser.GetvalueByType"
"GetValueByType is not available in database replication.jar"
Please suggest the solution
The flat file exporter doesn't use the replication.jar, it isn't even included in the module package. To use the flat file exporter package (until a new version is released) perform the following steps:
List <mendixobjectreferenceset> refsets =exportObj.getReferenceSets(getContext());
List refsets =exportObj.getReferenceSets(getContext());
List<imendixidentifier> objs = refset.a;
List<imendixidentifier> objs = refset.getValue(getContext());
That's all there is to it to get the module working in your Mendix version. I think the replication.jar file is being used by other modules in your project or maybe this was used in an older version of model reflection and might be giving issues when you have upgrade the project. With the method described above you should be able to export your data as described in the documentation in the appstore.