No mux options in Ventrilo: How to get this media Codec for Vista 64?

I want to be able to play music and talk while using Ventrilo. However, when I go to change the settings I get the error: "VoiceCommMixerStart: Invalid voice mux selection. (-1)". I run vista 64, I don't have a cd, I am not sure what I should be looking for to get this codec. Any suggestions? Thanks!

Also, I found these instructions at the ventrilo faq page, but like I said I don't have a CD, I don't run XP, and I have no clue if "Microsoft GSM 6.10 Audio CODEC" is correct for my OS.

::::
Q: Unable to initialize the codec. CODE = -1

-1 means the codec isn't installed. For some unknown reason some people do not have the codec installed even though the base install of the Operating System should have put it on. The following instructions are for Windows XP but should apply, with minor changes to Windows 2000. If you are using a Windows 9x system then put your install CD back on and reinstall all of the media files.

You accept all responsibility for any possible damage caused to your system if these instructions do not work. If you are not comfortable following these instructions then you should call Microsoft support and ask them how to do it.

1) Start.
2) Control Panel.
3) Printers and Other Hardware. (Win2000 users use "Add/Remove Hardware")
4) Under See Also click the Add Hardware. (Next)
5) Select the "Yes, I have already connected the hardware". (Next)
6) Scroll to bottom and select "Add a new hardware device". (Next)
7) Select the "Install the hardware that I manually select from a list". (Next)
8) Select "Sound, video and game controllers". (Next)
9) Select "(Standard system devices)" then select "Audio Codecs".
10) Click "Have Disk"
11) Click "Browse"
12) Browse to c:\windows\system32 (or c:\winnt\system32 for Win2000)
13) Select the "mmdriver.inf" file. (Open)
14) Click OK to "Install from Disk".
15) If asked about Windows Logo testing just click Continue anyway.
16) Select "Microsoft GSM 6.10 Audio CODEC". (Next)
17) Select Auto-Configure, which should set both Comp and Decomp to 44100 each.
18) Click OK.
19) Click Finish.
20) Reboot and pray that it works.