I've tried running from the PC's Administrator account, still without success.
Which doesn't necessarily run things with admin. access (on versions after XP, certainly with 7; never used Vista so don't know).
You need to check the title bar, as I said before, having used the "Run as administrator" option on the "Command Prompt" object's menu.
@are_we_humax - But how are you running it as Administrator?I am running as Administrator.
As everybody is trying to tell you, being logged in as administrator isn't sufficient. Personally I use All Programs>Accessories and then right click and select Run as Administrator on Command Prompt.It's beginning to look like a protection thing, though I am running as Administrator.