ORA-600 [12501] Error ??

Guys,

I came across this error in ALRT log file.

ORA-00600 Internal error [12501]

 It happened during this SELECT statement and it returned no rows,

        after i dropped an index on FROMPROFNO column.

SELECT NAME,AGE,SEX FROM MSGHISTORY WHERE
( MEMNO = 123 AND PROFNO = 456 AND FROMMEMNO = 789 AND FROMPROFNO = 910 AND SEX='MALE' AND POINT=1)
OR

( MEMNO = 124 AND PROFNO = 457 AND FROMMEMNO = 789 AND FROMPROFNO = 910 AND SEX='MALE' AND POINT=1)
this statement was working fine and was returning rows b4 i dropped the index.

as soon as i created an index on FROMPROFNO , it returned rows.

why is it behaving so ?
whether is there or not , i should be getting the rows. but it is not so ?

if there is index , i get the data and if it is not there i dont get data.

and what may be reason of ORA 600 [12501] error ? when is this error expected ?

help me guys ?

TIA.
Jp.

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Author: Prem Khanna J
  INET: jprem_at_kssnet.co.jp

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