Stupid error upon running Unity

Hi
I’ve decided to give Unity 3D a shot, however upon running the program i get this error message:

Writing file error
Resizing c:\program files\unity\projects\temp\tempfile 3 failed

any ideas what that might be?
Thanks

I get this too. This is explained in the sticky support FAQ’s. With me it is anti virus software.

2 Solutions - Make an exception in the anti virus software to the projects location (I don’t bother with this anymore)

or press try again and Unity will continue (although you will need to do this a few times when creating a new project.)