|Where are you located, US or Europe/Asia?|
Is your default date:
12/31/2011 Month Day Year ?
31/12/2011 Day Month Year ?
I do not know how you are getting 9/1/1901 from entering 06/10,
but you can try a Custom Format and see how that works.
Right click on the cell with your Date
Select Format Cells
Select Custom, at the bottom of the popup window
In the small input box, under the word Type:
delete what ever is in the box and enter:
MM/DD for Month Day type of date
DD/MM for Day Month type of date
As long as your cell contained an actual date then you should see it change.