I'm using MC 11.1.186 so I don't think the problem is because of an old MC version. System info posted below.
It seems that the encoder is available from the MC plug in page, but not the decoder. If the decoder is what can take you back to a WAV file, then I consider that a necessity.
Does the zip folder have to be in a certain place? Also, I still have MC10 on my machine, could that cause a problem?
Media Center Registered 11.1.186 -- C:\Program Files\J River\Media Center 11\
Microsoft Windows XP Workstation 5.1 Service Pack 2 (Build 2600)
Intel Pentium 4 2385 MHz MMX / Memory: Total - 523 MB, Free - 125 MB
Internet Explorer: 6.0.2900.2180 / ComCtl32.dll: 5.82.2900 / Shlwapi.dll: 6.0.2900 / Shell32.dll: 6.0.2900 / wnaspi32.dll: 4.71 (0002) , ASPI for Win32 DLL, Copyright © 1989-2002 Adaptec, Inc. / Aspi32.sys: 4.71 (0002)
Ripping / Drive D: SAMSUNG CD-R/RW SW-240B Mode:ModeSecure Type:Auto Speed:Max
Drive F: ATAPI DVD DD 2X16X4X16 Mode:ModeSecure Type:Auto Speed:Max
Digital playback: Yes / Use YADB: Yes / Get cover art: Yes / Calc replay gain: Yes / Copy volume: 32767
Eject after ripping: Yes / Play sound after ripping: No
Burning / Drive D: SAMSUNG CD-R/RW SW-240B Addr: 1:0:0 Speed:16 MaxSpeed:40 BurnProof:Yes
Drive F: ATAPI DVD DD 2X16X4X16 Addr: 1:1:0 Speed:40 MaxSpeed:40 BurnProof:Yes
Test mode: No / Eject after writing: Yes / Direct decoding: Yes / Write CD-Text: Yes
Use playback settings: No /