selenium - getting a 'The IWebDriver object must implement or wrap a driver that implements IHasInputDevices.' error -

im newbie in c# , selenium.

im trying create element extension mouseover element. i've got following:

public static void mouseoverelement(this iwebelement element, iwebdriver driver) {                actions actions = new actions(driver);           actions.movetoelement(element).perform();  } 

and called class

public mlinks mouseovercandidate() { candidatemenu.mouseoverelement(driver); return this; } 

and call test:

new homepage(driver, server)     .mainlinks.mouseovercandidate(); 

i don't quite understand. i've got driver set. can me out on this? thanks

system.argumentexception : iwebdriver object must implement or wrap driver implements ihasinputdevices. 

the method mouseoverelement taking iwebdriver, interface.

the concrete driver class implements interface, other interface ihasinputdevices.

so need pass in concrete class, can expose ihasinputdevices, iwebdriver