Follow this and it should works...
Right click on My Computer and then Properties, then click on Advanced, then you will see Performance settings, click on Settings then new window will appear. Click on the tab Data Execution Prevention and then select Turn on DEP for all programs and services except those I select then click Add find mu.exe which is located in our client folder and then click Open. After you added mu.exe in the list you must add main.exe which is located in our client folder too. Click Apply and then OK. Then you can try to connect to server. If still not work after the change try to restart your PC and connect again.