connection is expecting a read

Hi everyone i have this issue, i have a stored procedure like this:

SELECT @[EMAIL PROTECTED]
 = (SELECT MAX(CONVERT(INT,Load_Begin))
                              FROM SES
                              WHERE PMM_DATETIME BETWEEN @[EMAIL PROTECTED]
 @[EMAIL PROTECTED]
)
SELECT ISNULL(@[EMAIL PROTECTED]
)
SELECT @[EMAIL PROTECTED]
 = (SELECT MAX(PMM_DATETIME)
			   FROM (
				SELECT  MAX(Load_Begin) AS 'Max_Load_Begin',
					PMM_DATETIME
				FROM (
				    SELECT PMM_DATETIME, MAX(CONVERT(INT,Load_Begin)) AS
'Load_Begin'
				    FROM SES
				    WHERE PMM_DATETIME BETWEEN @[EMAIL PROTECTED]
 AND @[EMAIL PROTECTED]
    GROUP BY PMM_DATETIME
				) A1 ) A2)
SELECT ISNULL(@[EMAIL PROTECTED]
())


so the resul of this is:

100
The SQL Server is terminating this process.

20:09:57.927	DBMS	BIZARRODB -- Error:  Layer (5), Origin (2), Severity
(7), Number (12) ct_send(): network packet layer: internal Client
Library error: State error: trying to write when connection is
expecting a read., Batch -1 Line -1


as you can see the first calcule is good, it return 100, but the
second is the problem, so i put this out of the stored in a isql
console and it returns:

DECLARE @[EMAIL PROTECTED]
 DATETIME
SELECT @[EMAIL PROTECTED]
 = (SELECT MAX(PMM_DATETIME)
                                   FROM (
                                        SELECT  MAX(Load_Begin) AS
'Max_Load_Begin',
                                                PMM_DATETIME
                                        FROM (
                                            SELECT PMM_DATETIME,
MAX(CONVERT(INT,Load_Begin)) AS 'Load_Begin'
                                            FROM SES
                                            WHERE PMM_DATETIME BETWEEN
'2008-01-01 00:00:00' AND '2008-01-01 00:04:59'
                                            GROUP BY PMM_DATETIME
                                        ) A1 ) A2)

SELECT @[EMAIL PROTECTED]
 result:

1 row(s) affected.


[NULL]


so i dont understand why happens this with the sp, help please!!!