Is it normal to have pending data packets? What exactly does this mean?

These are pending messages. So it is normal to have them as users will have their BB off, out of coverage, etc..

All blackberries are on, messages have been pending for 11 days. Users have not been recieving messages, calendars not synced, contacts either. If you had any idea where to start I would really appreciate it. For BlackBerry Enterprise Server v4.1 for Microsoft(R) Exchange: Service Pack 4 and Service Pack 4 Maintenance Release 4

Restart the server and then look to your BES Logs. By default they are in:

C:\Program Files\Research in Motion\BlackBerry Enterprise Server\Logs

In specific check out ALRT and CTRL ... and then MAGT. Post anything that you have a question about.

Thank you very much for your help. BTW problems occured at the same time we upgraded to Service Pack 4 and Service Pack 4 Maintenance Release 4. Will post questions shortly