WHS 2011 - Based on Windows Server 2008 RC2, Shares base with Windows 7
x64 Install, 32Bit Java, CCCP Codec Pack (minus HP-MPC bits)

Tried both AviSynth 2.57 and 2.58
Also tried AviSynth 2.57 Base, AviSynth 2.6 MT Set 
Also tried AviSynth 2.58 Base, AviSynth 2.6 MT Set
UMS 1.0.1

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Disabled MT in AviSynth settings, Tried with Enabled also
main UMS Transcoding = 2 threads.

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File 1 - avi

2012-06-04 14:39:07 Transcode - Mencoder
Worked

2012-06-04 14:42:14 Transcode - AviSynth/Mencoder
Process C:\Program Files (x86)\Universal Media Server\win32\mencoder.exe has a return code of 1!

2012-06-04 14:46:05 Transcode - AviSynth/FFmpeg
Process C:\Program Files (x86)\Universal Media Server\win32\ffmpeg.exe has a return code of -1073741676!

File 2 - avi

2012-06-04 14:49:03 Transcode - AviSynth/Mencoder
Process C:\Program Files (x86)\Universal Media Server\win32\mencoder.exe has a return code of 1!

2012-06-04 14:51:24 Transcode - AviSynth/FFmpeg
Process C:\Program Files (x86)\Universal Media Server\win32\ffmpeg.exe has a return code of -1073741676!

File 3 - mpg

2012-06-04 14:57:07 Transcode - AviSynth/Mencoder
Process C:\Program Files (x86)\Universal Media Server\win32\mencoder.exe has a return code of 1!

2012-06-04 14:59:29 Transcode - AviSynth/FFmpeg
Process C:\Program Files (x86)\Universal Media Server\win32\ffmpeg.exe has a return code of -1073741676!

2012-06-04 15:01:18 Transcode - tsMuxer
The video will not play or show a black screen on the ps3...

File 4 - vob

2012-06-04 15:03:31 Transcode - AviSynth/Mencoder
Process C:\Program Files (x86)\Universal Media Server\win32\mencoder.exe has a return code of 1!

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Results seem the same with most files Tried.
Results are the same with PSMS v1.51.0 on same machine.

Have also tried K-Lite codec pack

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These files all play on WinXP using PSMS v1.51.0 up, CCCP and AviSynth 2.57, vsfilter