Cannot find row when using 3 indices for search, able to find it using only 2

[Constantin Teodorescu]

Cassandra 0.7.4 on 4 nodes Linux Ubuntu 10.10 i386 , 32 bit

root@bigcouch-106:/etc/cassandra# nodetool -h 172.16.1.106 ring
Address         Status State   Load            Owns    Token

172.16.1.104    Up     Normal  1.8 GB          22.33%
 4778396862879243066278530647513341098
172.16.1.8       Up     Normal  1.48 GB         28.12%
 52627163731801348483758292043565262417
172.16.1.106    Up     Normal  1.21 GB         27.22%
 98934176951395683802275136006692518904
172.16.1.110    Up     Normal  1.12 GB         22.33%
 136934291168078629024171054299313117062

I am using keyspace 'bnd' , columnfamily 'pet' described as

update column family pet with column_metadata = [
  {column_name: P_cui,          validation_class:UTF8Type, index_type:
KEYS},
  {column_name: P_nume,      validation_class:UTF8Type, index_type: KEYS},
  {column_name: P_prenume, validation_class:UTF8Type, index_type: KEYS}
];

Trying to find a row using 2 indices (P_cui and P_prenume) works:
[default@bnd] get pet where P_cui='1670518330770' and
P_prenume='CONSTANTIN';
-------------------
RowKey: RO1492360605
=> (column=A1RO354000086663, value=313a463a323030332d30342d30313a32333730,
timestamp=1303181522507175)
=> (column=P_adresa, value=4c4954454e49, timestamp=1303181522507175)
=> (column=P_cui, value=1670518330770, timestamp=1303181522507175)
=> (column=P_nume, value=Manoliu, timestamp=1303181522507175)
=> (column=P_prenume, value=CONSTANTIN, timestamp=1303181522507175)
=> (column=P_tip, value=36, timestamp=1303253832349129)

1 Row Returned.

I am able to find it using the other 2 indices (P_prenume and P_nume) works
fine:
[default@bnd] get pet where P_prenume='CONSTANTIN' and P_nume='Manoliu';
-------------------
RowKey: RO1492360605
=> (column=A1RO354000086663, value=313a463a323030332d30342d30313a32333730,
timestamp=1303181522507175)
=> (column=P_adresa, value=4c4954454e49, timestamp=1303181522507175)
=> (column=P_cui, value=1670518330770, timestamp=1303181522507175)
=> (column=P_nume, value=Manoliu, timestamp=1303181522507175)
=> (column=P_prenume, value=CONSTANTIN, timestamp=1303181522507175)
=> (column=P_tip, value=36, timestamp=1303253832349129)

1 Row Returned.

--------------------------------------------------------------------------------------------------

Trying to find the same row using 3 indices not working:
[default@bnd] get pet where P_cui='1670518330770' and P_prenume='CONSTANTIN'
and P_nume='Manoliu';

0 Row Returned.

Any clues?
Teo