DTM test for CIR device

I tried to take the DTM test for Microsoft's CIR device which I purchased
before. Long-range receiver can pass all the test cases but learning receiver
can't pass test case 6, 7 and 26. The error message reported by task log is
listed below.
Test case 6: RC6 key blasts were not reporte as window messages.
Test case 7: Blasted data to DUT but never received a data end event.
Test case 26: Blasted date from control device but never received a data end
event from the DUT.
Does any one know how to deal with this problem? My CIR device had been
signed by Microsoft, so it is strange that it can't pass DTM test.