This device is restricted from downloading this file type

[DarrenUtd]

Something happened recently to my Sprint Touch Pro that caused (at least) the following:

(1) I cannot download CAB files using PIE, i get the message in the post title.
(2) I cannot install CABs, the installation always fails.
(3) "Remove Programs" in Settings is empty.

So it seems as if some security settings have been messed up. I have searched everywhere and cannot find a solution for this. I did install Twikini recently, and have heard of others who had the same problem after doing so (so beware of this). Not much else is changed on my device. It just happened a few days ago.

Does anyone know how to fix this?

Is there something in the registry that I can fix? Where would it be, HKLM\Security? Can someone export their settings and post them?