Some images not showing up

I can t get my next and previous images to appear on my scheduler. I have images in a imgs directory but they are not appearing.

Can you provide us some kind of a demo, or link to the page where it can be checked?
btw, what skin do you use? Images for ‘glossy’ and ‘terrace’ skins should be stored in ‘imgs_glossy’ and ‘imgs_dhx_terrace’ folders respectively