Unable to start wptdriver.exe

Hi,

I have configured the Private instance by following the steps given Configuring an ‘all-in-one’ WebPageTest Private Instance

When I click on the wptdriver.exe in start up folder, i have received the below error

‘The application has failed to start because wpthook.dll was not found. Re-installing the application may fix this problem’.

Could some one please suggest me the steps to resolve this issue.