Error during Qt SDK Installation

Hi,
I am trying to install offline Qt SDK version 1.2.1on windows.
I get the following error:

â€œError during installation process(com.nokia.ndk.tools.madde.usbdriver) : execution failed(Unexpected exit code: -2147418112): â€œC:\QtSDK\Madde\usbdriver\DPInst.exe /SE /SA /SWâ€â€œ

If I ignore the error, the installation continues but I guess not everything is installed properly. I just checked building simple GUI application, no issues.
But help is not installed properly. I am not sure what else problems it may cause in later stages!

I tired to do online installation. But I get the following error and installation has to be aborted:
Error: Connection refused.
Could not fetch Updates.xml from repository: http://nds2.fds-forum.nokia.com/noki...ine_qtsdk_repo.

I must mention the following as well:

I work on a system for which I do not have administrator rights. So, the software is installed on my system from admin login. I do get the above mentioned error while installing even when installed with admin rghts. However, when I launch the Qt Creator in admin mode, sample application builds fine and help also is installed properly.
But in my login (no admin rights and can't be given due to security reasons), sample application builds but no help I can access.

So, following are my problems:

1. I get installation error whether I have admin rights or not.
2. Help is accessible only in admin mode and not in my login.

I have a laptop at home and there Qt installation happens as smooth as butter. No issues at all. I am not sure why I am having trouble at my work place.

Pls throw some light.