I thought i'd explain how i got SkyDrive to appear in Computer so maybe you can try it out and see if theres something I missed out.
1. Upload a word document to your documents folder. When done, go to the folder that you uploaded to but dont click the file yet.
2. Make sure you're signed up to Office Web Apps beta. See image. I think this might be what was blocking people from accessing the folder.
3. When you done that and signed up for it, go to the uploaded document and you should see a new option called 'View' (see image). Click that.
4. It will open in the Word Web App for viewing. Click 'Open in Word' on the toolbar at the top.
5. When it opens up in Word, enter your credentials and the document should open.
6. Go to File > Save As and wait for the box to appear.
7. You should see the URL in the address bar of the save dialog as seen in the screenshot below. (by the way this is microsoft office 2010, it will look different in 2007 but you should still be able to see the URL).
8. Map it in My Computer as shown in my previous post.
I believe it wasnt working because its integrated with the Office Web Apps which is in beta, if your not signed up for it it may be blocking access to it.Shorter steps for Office 2010 beta
If you have the beta of Office 2010 installed, theres a shorter way to get it.
1. Make a new document, type some random text into it.
2. Go to File > Share > Save to SkyDrive. Click Sign In.
3. Fill out the login box that comes up and click OK.
4. Your folders will appear so you can click the folder you want to get the URL for. Then click Save As.
5. You will see the URL in the Save As dialog. (See screenshot for step 7 above).
I hope this works for everyone!