Downloaded the update..began the installer. It REQUIRES that you have the directx8.0 dv update. I'm past that with directx8.1. I'm not sure you can go backwards on directx updates, and the installer will not proceed with the 8.1 version installed.
I did the upgrade flawlesly, I have WinXP and DirectX 8.1. I beleive that there might be an error in your computers registry. Try downloading Directx 8.1 and installing again (might not work cause the system will probably detect as if you already have it). Get a program that will clean and fix your registry, this should get rid of your unused files (make sure you backup those files, most registry cleaning programs let you do so). If it still ain't working, then do a system restore to a prior date... Windows XP is still confusing you know :)
I've got 98SE and DirectX 8.1. The upgrade to 3.0a went through with only one tiny hitch ... i had to close ICQ. Other than that, the whole thing took about 2 minutes and worked fine.
Well, it wasn't even really an error. I just got a warning screen that Vegas was trying to update a file that was in use by ICQ, and would i please kindly close ICQ. I did so, clicked the continue button, and the installation completed on the first try.
hmmm...after failing again, I checked registry. aok. Ran directx8.1 diagnostic - everything aok. So...I reinstalled directx8.1 'again'. Then ran vv3.0a update. Update successful. Must've had something overwrite a newer version of some directx8.1 file with an older version. Anyway....i'm up & runnin! Thanks to all for suggestions!