OAL Generator

i got these errors:
1)
Event Type:      Error
Event Source:      MSExchangeSA
Event Category:      OAL Generator
Event ID:      9360
Date:            11/18/2007
Time:            12:13:47 PM
User:            N/A
Computer:      UPSILON
Description:
OALGen encountered an error while generating the changes.oab file for version 2 and 3 differential downloads of address list '\Global Address List'.  The offline address list has not been updated so clients will not be able to download the current set of changes.  Check other logged events to find the cause of this error.
If the cause of the problem was intentional or cannot be resolved, OALGen can be forced to post a full offline address list by creating the DWORD registry key 'HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\MSExchangeSA\Parameters\OAL post full if diff fails' and setting it to 1 on this server.  When OALGen next generates the offline address list, clients will perform a full OAB download.  After that time, the registry key should be removed to prevent further full downloads.
- Default Offline Address List

For more information, click http://www.microsoft.com/contentredirect.asp.

For more information, see Help and Support Center at http://go.microsoft.com/fwlink/events.asp.

2)
Event Type:      Error
Event Source:      MSExchangeIS
Event Category:      General
Event ID:      9646
Date:            11/18/2007
Time:            12:07:15 PM
User:            N/A
Computer:      UPSILON
Description:
Mapi session "/o=Dmatek/ou=Dmatek ISR/cn=Recipients/cn=Raphaelk" exceeded the maximum of 32 objects of type "session".

 For more information, click http://www.microsoft.com/contentredirect.asp.

For more information, see Help and Support Center at http://go.microsoft.com/fwlink/events.asp.
3)

Event Type:      Warning
Event Source:      Server ActiveSync
Event Category:      None
Event ID:      3033
Date:            11/18/2007
Time:            9:30:03 AM
User:            DMATEK\Asher
Computer:      UPSILON
Description:
The average of the most recent [200] heartbeat intervals used by clients is less than or equal to [540].  Make sure that your firewall configuration is set to work correctly with Exchange ActiveSync and direct push technology. Specifically, make sure that your firewall is configured so that requests to Exchange ActiveSync do not expire before they have the opportunity to be processed.  For more information about how to configure firewall settings when using Exchange ActiveSync, see Microsoft Knowledge Base article 905013, "Enterprise Firewall Configuration for Exchange ActiveSync Direct Push Technology" (http://go.microsoft.com/fwlink/?linkid=3052&kbid=905013).

For more information, see Help and Support Center at http://go.microsoft.com/fwlink/events.asp.
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