The VM's: Server 2003R2 x32 / Server 2008 SP2 x64
The server with the converter software installed on it and crashed: Server 2003R2 ent x64 / Server 2008R2 std.
The conversion of the VM's that did succeed on the above servers: Server 2008 SP2 x64/ Server 2003R2 x64.
So i can't say that it crashed because of the installed OS's.