Comment 13 for bug 95889

I CAN CONFIRM THIS, same issue since dapper
Same problem here with my Belkin F5d7050-4 rev 3002:
Bus 004 Device 003: ID 050d:705a Belkin Components
I think it is a driver conflict:
Does not associate!
creates wlan0/wmaster0 and refuses to connect/associate but is able to scan, serialmonkey drivers work fine only for wep, something was changed in the kernel that crashes wpa connections...
This is a tough card, there are four known verions of this card.
802.11g F5D7050 v.1xxxx Prism54
802.11g F5D7050 v.2xxxx rt2x00
802.11g F5D7050 v.3xxxx man: 050d dev: 705a rt2x00 <--- my card
802.11g F5D7050 v. 4001 ?
 ?
802.11g F5D7050 v.4xxxx man: 050d dev: 705c ZD1211

As you can see by the table there is only 2 known device ids. However v. 2xxxx is still believed to use the ralink chipset which is support under PCLinuxOS 2007. Version 4001of this card is unknown and the v. 40000 uses the ZD1211 chipset which is also support under PCLinuxOS 2007. If you haven't purchased this card yet but want to. Take extnreme caution in making sure there's a decent return policy at the store. As by looking at the box you may not know what version you will be stuck with.
Quick Glance Specs

Network Type: Wireless Ethernet - 11 Mbps IEEE802.11b,
Wireless Ethernet - 54 Mbps IEEE802.11g
Device Type: Network Adapter
Port Types: USB - Universal Serial Bus 1.0/1.1,
USB - Universal Serial Bus 2.0

Wireless Device
Number of Antennas: 1
Device Type: Network Adapter
Network Status Indicators: Link Status

Networking Standards
Wireless Security Features: WEP - 128-bit,
WEP - 64-bit
Features: Integrated Antenna
Speeds Supported: 54 Mbps
Network Architecture Supported: Wireless Ethernet - 11 Mbps IEEE802.11b,
Wireless Ethernet - 54 Mbps IEEE802.11g

Ports
Port Types: USB - Universal Serial Bus 1.0/1.1,
USB - Universal Serial Bus 2.0

Warranty
Warranty Information: Limited Lifetime Warranty

this is from the pclinuxos database, its a shame it works fine in other distro's and not ubuntu but we will get it fixed for ubuntu eventially!