MySQLdb insert fails on one table

[Sells, Fred]

I have this table

mysqldescribe valid_individuals;
+-------+--------------+------+-----+---------+-------+
| Field | Type | Null | Key | Default | Extra |
+-------+--------------+------+-----+---------+-------+
| fname | varchar(30) | YES | | NULL | |
| lname | varchar(30) | YES | | NULL | |
| alias | varchar(30) | YES | | NULL | |
| email | varchar(100) | YES | | NULL | |
+-------+--------------+------+-----+---------+-------+
I call this function

def insertRecords(self, tablename, columnnames, values, clear=True):
cursor = self.Connection.cursor()
sql = "INSERT INTO %s (%s) VALUES (%s)" % (tablename,
','.join(columnnames), ','.join(['%s' for x in columnnames]))
print >>sys.stderr, sql, values[:3]
cursor.executemany(sql, values)
cursor.close()
which prints:
INSERT INTO valid_individuals (fname,lname,alias,email) VALUES (%s,%s,%s,%s)
[['xxxx', 'yyyy', 'zzzzz', 'aaaaaa']]

this function works fine for several other tables, but on this one I get no
errors and there is nothing in the table. If I run the equivalent insert on
the command line, it's just fine.

I'm lost here; Python 2.4.4 and latest MySQLdb for 2.4.4; anyone got a
clue?

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