You still need to enter a filename (your choice) in the field as indicated. Have you tried it?
I have replaced the OpenFileDialog with SaveFileDialog and the result is also shown below. As you can see it says "Save As" in the title bar, in the folder section it says "Save In", the "Open" button has changed to "Save", and a another change to "Save as type" which we don't use. Some textual changes but otherwise the same.
Both dialogs work more or less the same. The fact that they are so similar can make one miss the mistake of using the wrong dialog. The dialogs are used only to select a file, not to actually read or write them.
On your screenshot I can't make out an icon with which you can create a new folder. That might be a difference for W7 and you may have to create it in a different way (just checked the internet: there seems to be a problem with W7 regarding folder creation, even for an administrator
);
In the next release of CTC, we will have the dialog changed, but the functionality will remain the same - most likely.