I have checked locally in our site but everything is fine here. I have assigned a developer for your issue. But he is now in weekend. He will be available from monday. Please keep patience and after his coming back i will inform you the update.
Actually i did not get any kind of error like as your one. So it is very complicated for me. Can you please provide your login details by using this form- http://wedevs.com/provide-login-details/. I will have a look what is going wrong. Also i need your ftp details. Please provide your ftp details in a private reply.
I know that you have provided your details but this error was occurring for the latest version of WordPress. Our maximum Dokan user asked for fix of this problem. Fixing this problem by taking site details one by one it was very complicated for us. For that we have released a update. I know you had to wait for a week. I am really sorry for that.