Hi and welcome,
It's very strange and unfortunate that your client crashes upon trying to login and play.
First thing you should do is check if your computer drivers are up to date.
(If you don't know how to do that you could download a nice little program called Driver booster)
Alternatively you could try and run the client (Trose.exe) in compatibility mode, I suggest to try Windows XP first and see if that helps.
Go to your Rose online directory folder "in my case this is C:\Gravity\ROSE Online" but it might be different for you.
Locate and right click the Trose.exe file and go to properties, select the tab compatibility, next check the box for the compatibility mode, then select Windows XP (Service Pack 3) if that doesn't work you could try the Windows 7 version to.
I hope this will solve your problem, good luck!