The problem was that your ID column wasn't getting any value. I saw on the SQL Fiddle that you declared the ID column with
DEFAULT newid and I didn't..
MSDN Documentation for you Here
To add a bit you can convert a string to a uniqueidentifier using a following code
If that doesn't work check to make sure that you have entered the valid GUID
I had also faced the similar issue in the recent past. I did lot of research on it and found the solution on it. This is the very common problem with the people getting started.
DECLARE @t TABLE (ID UNIQUEIDENTIFIER DEFAULT NEWID(),myid UNIQUEIDENTIFIER, friendid UNIQUEIDENTIFIER, time1 Datetime, time2 Datetime)
insert into @t (myid,friendid,time1,time2)
values ( CONVERT(uniqueidentifier,'0C6A36BA-10E4-438F-BA86-0D5B68A2BB15'),CONVERT(uniqueidentifier,'DF215E10-8BD4-4401-B2DC-99BB03135F2E'), '2014-01-05 02:04:41.953','2014-01-05 12:04:41.953')SELECT * FROM @t