It looks like you haven't started the command prompt with the Houdini environment. You can do so using the Launcher by clicking the little down arrow next to the Launch button and choosing "Command Line Tools," or you can run hcmd.exe from that bin folder directly, which will do the same thing.
Once the command prompt appears, you can test for the environment by running the command echo %HFS%
That will display the HFS environment variable, which should be the simplified Windows path to your Houdini program folder (something like C:/PROGRA~1/SIDEEF~1/HOUDIN~1.550).
With the environment set up correctly, you won't need to enter the entire path to the utilities. The bin folder will be on the system path, so it's easiest to browse to the location of the image you want to extract stats from and run the command from there.
edit: Or, I suppose you could just look at the first few lines of the command prompt and see that it's been configured: