Houdini does not support folder Creation when Rendering, but you can run a python script before the render starts.
1) Put under your Mantra-Node under Scripts > Pre-Render-Script execfile(“$HIP/YOURSCRIPTLOCATION/YOURSCRIPT.py”)
2) Your pathParm should point to the ‘out/mantra1/vm_picture’ parameter of your Node.
Check if Folder-Exsists
3) The above code is as well up-counting the Version, but you should change it for your needs.