Query Filtering TCERS by Test Case Categories cannot be saved

I am using RQM 4.0.5

I have filtered my TCERs by "Test Case Categories" , nothing else. But when I save the query I got an error and the name of the new query is saved, but it retrieves all of the records, not the ones filtered by the test case category selected. the error message only says: "Error running query"

Is that a known issue? or am I doing something wrong?
Is there a workaround to save a query for TCERs filtered by Test Cases categories?

Thanks,
Isabel