wpr.exe: command line option "-onoffresultspath"

In the wpr.exe command line, there is this option:

  -onoffresultspath d:\tracelog

However, it does not store the final file there. Instead, it stores the file in the current directory. As the wpr.exe is started from within a batch file located in c:\batch, the final etl file is stored in c:\batch. So why does the command line option not work? (d:\tracelog does exist on a fixed, local hard drive)

Thanks

Armin