Admin Issues

I am unable to upload images using my OpenjCart admin and am looking to see if someone can find a fix for this. I have 2 OpenCart stores on one server and am having trouble with both. They are different OpenCart versions for each store. To give more detail: on one store the 'Images' tab doesn't open the pop up box to add images resulting in me not being able to upload any pictures to adverts. The other store, the pop up does appear however when uploading images to the folder, they do not display.