I too recently tried to create a Win 7 x86 VM in Hyper-V on a WS 2008 R2 box. Installe Haali and DVRMSToolbox 1.2.2.5. It successfully convert MKV files to WTV only they stutter badly. My only remedy has been to use Windows 7 and do the conversion on a physical hard drive (no VM) using SATA IDE mode and NOT AHCI. AHCI also causes the stutter. It's sad todvrms.exe doesn't run well in a VM. Not quite sure what causes the issue.