Does the Samsung Galaxy S2 support WPA2 with AES? I'm trying to connect my Samsung Galaxy S2 to my TP-Link WA801ND Access Point. This works when I disable Wireless security but when I enable WPA2, the mobile refuses to connect.

Does the S2 support WPA2?
The original SGS supports WPA2 with AES, so I would bet that the SGS2 does.  There seems to be a glut of routers that don't play nicely with non-PC devices when using WPA, for whatever reason, so I would suspect that's your issue.