Same this problem i am facing my client application is WinForms application C# 4.0
When i read the solution here, i checked Date & Time of client computer, but that was right and current time was showing, but still i was facing these problem.
After some work-around i found that wrong time zone has selected, i am in India and time zone was of Canada, the host server is located in Kuwait.
I found that system converts time to universal time.
When i changed the time zone to India's time zone, the problem was soled.