ok so couple thoughts/questions then - do you double click or drag to put the flower in the machine? i couldnt do either. and 2nd - i couldnt make the wolf tablet work either. same issue. i just figured it was a bug and ran in through the poison cloud.
Click the machine, click the empty space on the right once it open up, it pops your inventory up then should be able to double click the item in the inventory or drag it over to the spot (think the click works best). Just make sure its in the inventory of the person actually using it. I haven't seen any other workstation bugs in the forums so hopefully its just being finicky. I know Ive had to mess with it a few times to be like "ah, there it goes"