I wonder if you and I are having the same issue. My drive how ever is not full, far from it.
Here is my setup, two laptops, one running XP and the other Vista. I have the Linkstation connected to a D-link DIR-655 Gigabit router. Everything worked fine until recently, I have around 50GB of data on the Linkstation.
Now the share folder directory shows blank on both computers!. Everything else works I can access the drive, do web admin even update firmware (which I tried), my drive firmware is at 2.10
The strange thing is if I run a Disk Check from the web admin for a few seconds after the check I can read the directory and even open files but after around 10 seconds the directory goes blank again. I have also tried connecting the laptop to the router with a cable just in case the issue is my wireless network.
I have tried a lot of things (Flashing firmware, reseting to default, etc...) but I know it is not OS related since each laptop is running a different OS.
I can open and read the files in the "info" folder just not the "share" folder.
Try running a check disk from webadmin and immediately after check your share, do you see your files for a short period?