Strange SQL problem

Hi guys,

I have an SQL query I am running. The query looks as follows;

SELECT TIME_STAMP, MSISDN, SUM(SUCCESS_2G), SUM(SUCCESS_3G)
FROM
(
SELECT D.TIME_STAMP, I.MSISDN, A.SUCCESS SUCCESS_2G, 0 SUCCESS_3G
FROM TABLE_1 A, DAY_TIME_DIMENSION D, IMSI_MAPPING I
--WHERE D.TIME_STAMP = TRUNC((SYSDATE-75),'DD')
WHERE D.DATE_ID BETWEEN 3348 AND 3354
AND A.IMSI_ID=I.IMSI_ID
AND A.DATE_ID=D.DATE_ID
AND I.MSISDN=12345678
UNION
SELECT D.TIME_STAMP, I.MSISDN, 0 SUCCESS_2G, B.SUCCESS SUCCESS_3G
FROM DAY_TIME_DIMENSION D, TABLE_2 B, IMSI_MAPPING I
--WHERE D.TIME_STAMP = TRUNC((SYSDATE-75),'DD')
WHERE D.DATE_ID BETWEEN 3348 AND 3354
AND B.IMSI_ID=I.IMSI_ID
AND B.DATE_ID=D.DATE_ID
AND I.MSISDN=12345678
)
GROUP BY MSISDN

When I run the query in DBvisualiser it works fine but when I try and run it on a linux system it just hangs. I have tried altering the query but nothing seems to work. Any suggestions. Thanks in advance.