Same error in vehicle detection.. How to solve.. Which one to use..?

[datasciencecompleteguide]

https://github.com/duyet/opencv-car-detection
You can use the cars.xml file from the above repository and make sure that you have given the correct location of the "cars.xml" file.

Like in the image you can see that I have copied the repo. from the above link on my desktop and given the complete location of the image as well as cars.xml file.

See the output:

Hope it helps.