Error while refreshing the BO WebI report

Dear Friends,

I have created BO report on top of BICS Query in BO 4.0(have used aroung 15 BICS queries in to the report) and able to see the correct data.

I have used hierarchies and also selected levels in to webI report. Last week I am able to refresh the report but since two days I am getting some strange errors.

Errors:

1) Unable to run the empty Query.

2) When trying to invoke the method com.sap.ip.bi.bics.dataacess.consumer.queryview.results.et.IRsAxisTupleelement.Getcharateristicmember() of an object loaded from Local Variable 'element'(WIS00000)

Can you please help me on this isse.

Regards,

Eswar