Please input valid unsuspend date


while trying to change the status of interation record from "in progress" to "suspend" state, the wizard pops up, which asks for

Unsuspend Date
Update Type

Upon, giving the above required inputs, i am getting message as "Please input valid unsuspend date", i tried using various dates in the field of "ususpend date", but no luck.

attached screen shot for quick reference.
kindly suggest what could be the solution to prevent the occrance of error message

Thanks and Regards
Hemant Vaswani