Saved games are located under the default folder:
Win7 and Vista
C:\Users\<USERNAME>\Documents\The Adventures of Tintin
Win XP
C:\Documents and Settings\<USERNAME>\My Documents\The Adventures of Tintin
Win7 and Vista
C:\Users\<USERNAME>\Documents\The Adventures of Tintin
Win XP
C:\Documents and Settings\<USERNAME>\My Documents\The Adventures of Tintin