If you've made your selection already (totem near the Barrier teleporter shrine), why do you need to talk to Wesson? You should be able to, but you don't need
At worst you may miss out on Radcliff and Wesson making a couple weapons, but they are not really that great.
Try teleporting back to Broken Valley, then return to Sentinel Island and see if that allows you to talk to Wesson.
If that doesn't help you can email your latest save to firstname.lastname@example.org, or email@example.com. Mention which version of the game you have (D2:ED, DKS or D2:DC) and game language (if other than English).
In XP the saves are in the folder
C:\Documents and Settings\<UserName>\Local Settings\Application Data\Divinity 2\Savegames
or in Vista, Win 7/8
You may need to set Windows Explorer to show hidden files and folders (XP, Vista
, Win 7
, Win 8