I will suggest you to execute this Idoc in test mode (WE19) in forground. This is really helpful.
Looks like inbound Idoc do not have correct date.
1. Yes, you are right TKNUM indicates Shipment number
2. For Transportation planninning point 2000, check below thread. This has details of ow to fill Transportation planning point in shpmnt05 Idoc type.
http://scn.sap.com/thread/1719644
Regards