Plague here, pleased to meet you!
(I'm one of the blokes who works on the iPhone version of the Titanium engine.)
Most of the Appcelerator team uses Mac OS or Linux, where uninstallers aren't needed, and the installer was made with cross-platform codebase in mind. Martin's been working on native installers (MSI, PKG, etc) but I don't remember if it made the latest version. I figure the uninstaller on Windows should show up by the time we hit 1.0 or so.
So what did it not do for you? iPhone development does require Mac OS 10.5 or later, since it uses the native iPhone SDK. You will need to use your own text editor, since we're focusing on the actual making-the-app instead of reinventing the text editor, but any good dev already has a favorite.
If you're still having trouble with programming, take a look at
http://www.appcelerator.com/community/titanium-quick-start/
If you still don't trust our code, go ahead and download it all at
http://github.com/appcelerator/
and you can inspect and build it yourself. (It's written in C, C++, and Objective-C for Mac/iPhone)
Anything else you need?