Is this the final Vista release?
If not, you can find the trace file qagentrt.etl in %windir%\system32
If yes, the tracing that you enabled will not generate trace files. You will have to use a workaround:
1. Type: logman start QAgentRt -p {b0278a28-76f1-4e15-b1df-14b209a12613} 0xFFFFFFFF 9 -o %systemroot%\tracing\nap\QAgentRt.etl -ets
2. run through the scenario
3. Type: logman stop QAgentRt -ets
The trace file qagentrt.etl will be generated in %systemroot%\tracing\nap
Note that these trace files are not human readable, you will need access to private symbol files to decode them.
Thanks
Ram