having cropped positive samples is ok.
you still need an annotation txt file, containing a line for each image:
/full/path/to/pos_image 1 0 0 48 48
however, cropped negatives are a problem, since the training tries to crop many (like hundreds) neg “windows” from a larger image. if your neg image only has a singe window, 10000 might not be enough
at least show the resp. cmdline, and the resulting errors, please
p.s. the HOGDescriptor expects cropped images like yours, might as well try to train one of those, too.