I have made some progress. I managed to get the tongs out of the table, and now it has that blue light around it, like notes do. But I still can't pick it up. I have attached to this reply screenshot from the game. I would like to mention, that in the game my cursor is pointed directly to the item. For some reason I now can't interact with it at all. I can't pick it up, throw it, anything.
In the second screenshot is the folder where these tongs are. Just to show, that I made that inventory image, 60 x 60, .tga. I also attached the entity and the image to each other in the Model Editor. I checked the Maps folder, and there was not any .map_caches files.
If there is something else you would like me to show with screenshot, please, let me know. I really appreciate your help.
EDIT: I thought to add one more screenshot, just to show that I can interact with everything else in the game, so I think the problem must be in the item. I just don't know where to look the error anymore.