Logon Error 18456

Hola a todos
Necesito ayuda para comprender el siguiente error que tengo en un servidor SQL 2005 Standard 64 (SP2).
El error lo tiene identificado Microsoft con Articulo ID: 937745 y el Hotfix "50001317", pero MS no da mucha información más, para saber el motivo exacto.
Ha alguien se le ocurre el motivo, configuración o que monitorizar para saber realmente la causa, o si ha tenido el mismo problema.
Gracias por vuestra compresión
Paco

thanks satya
I go to read these articles, but the symptoms error are described in http://support.microsoft.com/kb/937745,

SYMPTOMS
When you log in to an instance of SQL Server 2005, error messages that resemble the following are logged in the SQL Server Errorlog file:
Error message 1
2007-03-27 12:01:28.45 Logon Error: 18456, Severity: 14, State: 23.

Error message 2
2007-03-27 12:01:28.45 Logon Login failed for user LoginName'. [CLIENT: IPAddress] Additionally, error messages that resemble the following may be logged in the SQL Server Errorlog file if an existing connection is reused in the connection pool:
2007-04-23 13:18:09.380 spid4371 Error: 18056, Severity: 20, State: 29.
2007-04-23 13:18:09.380 spid4371 The client was unable to reuse a session with SPID SPID, which had been reset for connection pooling. This error may have been caused by an earlier operation failing. Check the error logs for failed operations immediately before this error message. When this problem occurs, you may also experience the following symptoms:
•High CPU usage occurs.
•The Microsoft Windows operating system frequently performs context switches.This problem occurs when SQL Server handles many concurrent connections on a computer that has many processors installed. Additionally, a time-out may occur when you run a query.
CAUSE
This problem occurs because memory allocation contention causes a slowdown on the login process or the query execution process.

-- but the cause I don´t understand, is bad memory configuration set.., many connections (90) ..., a memory bottlenecks..., a symple "bug"...
Thanks

-- I have this error 4 times in a month, the hours have been different, I don´t identify any process what cause concurrency in sql.
-- The numbers connections are average 90-100, but in the error i don't have this counter.
-- Service pack 2
-- My counters, in performance monitor, don´t run in the error moment, and I don´t have information. ( I setting schedules for 24 hours). I hope to have more information.
-- No, I will review performed lock pages settings,
thank

Thank Satya
Sorry for my English

Gracias
Paco