0x8009000b can't join a homegroup

I get this error whenever I try to join my friends home group. And I have tried to google it already.

0x8009000b

anyone have any ideas about how to fix it?

I used to be able to join his homegroup, but now I can't do anything with homegroups, and I'm not part of any homegroup either.

Happens the same with me. I got two computers running W7. I installed it on a first one and while I was creating a new PC for my wife she was using the old one. So i was using three. And two of them using the same user... (the old one using XP). And I managed to join the homegroup at times in the new W7. On other times I couldn't but I thought it was due to using accounts with the same name. Now, with only the two W7 computers I can never join the homegroup in one of them...

I'm having problems with an Antheros LAN integrated card (and same problem with a Realtek chipset LAN PCI card...) - Must be from there...

to fix the 8009000b error, can you try deleting the contents of
C:\Windows\ServiceProfiles\LocalService\AppData\Roaming\PeerNetworking
C:\Windows\ServiceProfiles\NetworkService\AppData\Roaming\PeerNetworking
and rebooting?