by lnoland » 17. Jan 2011, 16:31
PROBLEM SOLVED
It would appear that the OP and I have been fighting different issues. Mine appears to have been due to UAC (user account control). Since the OP was having the same symptoms on Windows XP, I discounted UAC as being the issue.
I tried installing version 4.0 on a Windows Vista Home Premium 32-bit host and had the same problems installing the extender pack. The fact that I was seeing it on Vista and Windows 7 and (apparently) most people aren't seeing the problem at all, brought me back to suspecting UAC. On the Vista machine, I decided to try turning off UAC. I turned it off, rebooted, and tried the extender pack installation again -- it went without a hitch. (I then turned UAC back on, of course).
Encouraged by these results, I tried the same in Windows 7. It didn't work, however. It appears to me that, in Windows 7, they have changed UAC in a way that, I suspect, you can't truly turn it off. You can get it to stop asking you for permission, and apparently some things will then install with Administrator privileges without notifying you, but I suspect that some things it still blocks and I suspect that certain operations involving writing into the "program files" folder is one of those things (which is good, in my book, as I never liked the programs that would store their data and such in that folder, anyway). Some things do belong in that folder, however, and it would seem that the extender pack scenario is a valid one. It appears, however, that whatever hand-waving Microsoft requires in order for one to legitimately write into that folder (or subfolders) in the way an installer does, the VirtualBox developers must not have done that hand-waving on the part of the extender pack installation. At that point, I thought I might just be sunk until the VirtualBox developers addressed my ticket (if ever -- being a non-paying user, my ticket likely automatically winds up at the bottom of the pile and gets shuffled back there regularly). I then had another idea and this one proved successful: I rebooted the computer into Safe Mode and installed the extender pack from there -- it worked with no issues whatsoever! (Note: I don't know if it is significant but, I still had UAC turned off when I booted into Safe Mode.)
I hope this can help someone else having this problem. (To the OP: though your issue can't be caused by UAC, since it didn't exist in XP, if you are still having problems, you might want to try installing the extender pack in Safe Mode and see if it makes a difference -- even though turning off UAC was enough in Vista, it may be that the problem in Windows 7 and XP is actually something different and Safe Mode is the way to overcome it.)