Linksys Windows Media Extender

All,

I have recently purchased a WMCE54AG Extender and am having difficulty setting it up. I know the hardware is OK, as I have tested it on a another set-up that already have an extender installed.

Here's how the set-up should progress:
1. The welcome screen appears
2. It recommends that you stop any TV recording that is scheduled or in progress
3. License agreement
4. Installing software screen
5. Extender Activation policy screen appears
6. Microsoft Product Activation
7. It activates Media Center Extender software over the Internet
8. When successful, it will ask for the setup key
9. Extender connection which allows the program to change some settings on the computer
10. Content settings screen
11. Applying permissions
12. Content settings which allows the device to use the same folders in the PC
13. Enable error reporting
14. It will then try connecting to the media center extender
15. It will also create a user account
16. Media Center Extender Setup is finished. Finish button will then be available

Let me describe where my set-up has failed, to hopefully help you guys help me better. Could you review the attached and see identify what could be the issue causing these effects?

>Between step 7/8, the S/U 'Restarts' my machine, following the changes it makes to my configuration. It then continues S/U following 'Restart'.

>At step 10 or 11 below (not quite sure which), there is the option to enable the Extender to access all 'My Documents' files on my PC. If I 'check' the box, then S/U fails. If I don't 'check' the box, S/U continues.

>At step 12, if I 'check' the box, then S/U fails. If I don't 'check' the box, S/U continues.

At step 13, if I 'check' the box, then S/U fails. If I don't 'check' the box, S/U continues.

At step 15, S/U always fails.

So, it's seems to be a problem with setting up an Extender user account.

I've tried everything on configuration I can think of and trawled the web for help on this.

Here's some system data:
>PC: HP m1180 by the way (should not be an issue).

> Software: Windows XP Media Center Edition 2005
Ver: 5.1.2715.2773(xpsp(wmbla).051011-0745)
Update Rollup 2

So, I think it's down to a configuration or softwere issue.
Any guidance much appreciated. Thanks.