The patcher requires a certain charging time, wait a moment and look if he reacts after a few seconds.
Should your patcher / game close, or give an error message, probably you miss the requirements for playing.
In our download area you will find a link to the Microsoft page for DirectX and for the Visual Studio Packages wich is needed for playing. When downloading, pay attention to selecting the correct version for your system. (x86 for 64-bit systems)
Please note: If you arrived at the DirectX installation, make sure that DirectX is not only extracted but also installed.
Dark-Core Revolution runs on version 21 and has a direct X and 64 bit upgrade to get a better performence.
Such changes are simply not possible without some various system adjustments for older games like flyff.