Windows 7: Internet security settings preventing rundll32.exe on new user accts?

Hello,
I'm having this rather frustrating problem on new user accounts that I create on this computer (Windows 7 Home Premium 32-bit). It doesn't happen on my main account, but when I create a new one, whether it's a standard account or an admin account, it comes up with this when I try to change the keyboard layout. It does it on a few other things, too, and won't let me change the UAC settings (it doesn't respond when I click the OK button). Does anyone know why this is happening? Thanks



edit: The title should read "preventing rundll32.exe from opening", by the way.

The first thing I would blame is whatever security suite you may be using.
Some of them have a lot of little settings hidden in them regarding account creation and permissions.

...it's worth looking into at least.

I'm using Microsoft Security Essentials 4.0.1526.0, updated today. I can't seem to find any settings related to that there; would they be hidden in a menu to keep us ordinary users out?

edit: I've also done an sfc /scannow on the main admin account, and it found no integrity violations, if it's of any use.

Actually, never mind - I seem to have fixed it by importing the internet settings registry from my main account into the new account. Thanks anyway!

edit: The keys I imported were in HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Internet Settings, if anyone has the same problem.

Would still be nice to know what got them set wrong in the first place.

Goodness only knows...
If anyone has any ideas, feel free to post them!