Port open but No incoming connections

[HiHo]

The problem is that my utorrent has the "yellow exclamation mark" stating "no incoming connections". However, when I checked the forwarded port with the port checker, it states that the port is open and accepting incoming connections. So I'm trying to discover the reason for this as my download speeds are severely limited (~2.0kb/s).

My current setup is:

Internet -> D-link DSL 520t router (PPPoe mode) -> 4 port switch -> Wireless AP CWA-854

The computer concerned is connected to the Wireless AP wirelessly via antenna.

Port forwarded is 55555.

Firewall is Windows Firewall (have tested with firewall turned off and on to no effect).

Any help would be much appreciated.