Prompting For Credentials Problem

Im using the latest version of WinSCP ( 4.3.3) and i have an annoying problem.
When i upload something, after a while a window pop up saying Prompting for Credentials and i have to put my password in order to keep uploading. I had this problem in version 4.3.2 aswell.
When i upload something like in night and i go sleep i wake up and see 5% uploaded and Prompting For Credentials window.
How can i fix this and shut the stupid confirmation or what ever it is?

You need to enter the password on login dialog (not to wait for prompt during authentication), to make it be preserved in memory for reconnects.

But i already put my password when i log :x
And i hate it cuz it stops the uploading...
There is no way i can prevent the dialog from popping up making me put password all over again and again?