With version 2.7 (and 2.7.1rc1), the following sequence (see attached test):
   
   c =  cursor.execute(' select k from t where k == ?;', (1,))
   conn.commit()
   r = c.fetchone()

Traceback (most recent call last):
  File "/bugs/sqlite_bug.py", line 22, in <module>
    c =  cursor.execute(' select k from t where k == ?;', (2,))
sqlite3.InterfaceError: Error binding parameter 0 - probably unsupported type.

The program works with 2.6.2