try to replace the following part in your coding i hope it will work for you .

SELECT @lStr = N'DECLARE @tblAmount TABLE(LegalEntity VARCHAR(10), Amount MONEY );INSERT INTO @tblAmount (LegalEntity, Amount)'+

'SELECT LegalEntity,SUM(CAST('+ @ColName +' as MONEY)) AS Amount FROM dbo.' + @TableName + ' t(NOLOCK)'+

'WHERE t.AdjustmentBatch_ID = ' + CAST(@AdjustmentBatch_ID AS VARCHAR(20)) + '

GROUP BY t.LegalEntity select * from @tblAmount'

PRINT @lStr

EXEC SP_executeSql @lstr