File Uplaod Problem

hi there.. ive had a look around and still can seem to find the answer....

I uploaded about 60 picture files jpeg.. and they uploaded ok and when the list refreshed i only had 70% of the files i look at which ones where missing and dragged them across to upload again.. they uploaded ok but when the list refreshed they dissapeared... i also tried it with only 1 file but stll had the same problem..

If anyone can help me that would be great