There are three editions of Dynamic Disk Converter - Professional Edition, Server Edition and Unlimited Edition. Here is the differences or limitations among them.
Professional Edition
Server Edition
Unlimited Edition
Supports Windows 2000 Professional, Windows XP 32-bit and Windows Vista, Windows 7 32-bit.
Supports Windows XP 64-bit, Windows Vista 64-bit and Windows 7 64-bit
Supports Windows 2003/2008 Server (32 and 64 bit), Windows 2000 Server/Advanced Server