Try to use the GUI Spy to look at subwindow a: Do the displayed properties match with the properties stored in the GUI Map? Is the class-property of subwindow a of type "window"?
ad 2) The error message says that WR cannot find the toolbar item named "WinRunner-[c:\\documents and setting\\aa\\a1*]" within the system toolbar. Maybe you've stored the script, which made the asterisk at the end of the filename disappear - and that's enough for WR not to find this item... (and using regular expressions on the 2nd param of toolbar_button_press() is not possible).
I don't know why you need to click on the WR task - WR will automatically come up when your test is finished. Try to modify your script so that you don't need to do any automated actions against WinRunner.