Memory stick - camera says it is full but it is not?

I have two Sony ICES/NMB-003 Memory Sticks, one that is 16MB and one that is 64MB. There are no pictures on them, but when I turn on my digital camera the camera says there is no memory space. The only thing I can think of is that yesterday, I copied all my pictures onto my MacBook and from the open window for the memory sticks deleted them from the sticks, whereas I usually use the delete function on the camera itself. Deleting from the laptop allowed me to delete all at once instead of one by one.

There are no pictures on the sticks, but the camera says they are full. How do I fix this! I already tried going into one of the sticks on the laptop and deleting the folders themselves (DCIM, MISC, and a sub-folder in DCIM). Please help! I am on vacation and need to use the camera.