Device or resource busy Error

I'm trying to delete or rename a Directory on a Unix server and I keep getting this error whenever I try: "Device or resource busy"
It says the Directory has no files in it, so I don't understand how it could be busy.

Does anyone know how to delete this Directory? It's not my server, I rent it.
I know it's Unix, but not a lot about that...I get this when I log in:

[16:32:12] 220 ProFTPD 1.2.10 Server []
[16:32:12] USER usernamehere
[16:32:12] 331 Password required for usernamehere.
[16:32:13] PASS (hidden)
[16:32:14] 230 User usernamehere logged in.
[16:32:14] SYST
[16:32:14] 215 UNIX Type: L8
[16:32:14] Detected Server Type: UNIX
[16:32:14] FEAT
[16:32:14] 211-Features:
[16:32:14] MDTM
[16:32:14] REST STREAM
[16:32:14] SIZE
[16:32:14] 211 End


Hello ...

Please post the complete log.