From help:--
1.In the planning environment, select the planning area, level, and packages for which you want to edit data.
2.Expand the list of planning functions for the parameter groups with which you want to execute a planning function.
3.From the context menu of the parameter group, choose Execute with Trace.
The planning function is executed with the parameter group.
4.In the right-hand area of the screen, switch to the Trace tab page.
Go thru this link to know more..switch on the trace..the changes will then be available in the log..
http://help.sap.com/saphelp_erp2005vp/helpdata/en/1b/381151690a40a7b87d80882437c962/frameset.htm
Regards
Manga(Assign points if it helps!!)
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