You type should be
CREATE TYPE [dbo].[tblAnswerChoiceTypeUpdate] AS TABLE(
[AnsID] int,
[answerchoice] [ntext] NULL
)
The stored procedure should be
CREATE procedure [dbo].[spUpdateAnswerChoice] @dtanswerchoice tblAnswerChoiceTypeUpdate READONLY as
Begin
update tblAnswerChoice
set AnswerChoice=@dtanswerchoice.answerchoice
from tblAnswerChoice,@dtanswerchoice
where tblAnswerChoice.AnsID=@dtanswerchoice.AnsID
End
Hope this helps