It could be an issue with out-of-sync clocks.

Please check that your machine has the right time, and that Windows is configured for your time zone.

To maintain the right time automatically:

 Click on the clock in the Task Bar, to open the "Date and Time" preferences window. Go to the 'Internet Time' tab, then 'Change Settings' button. Make sure that there is a good choice for "Synchronize with Internet Time Server", then click the "Update Now" button.


Also, there please use the new Windows wallets: ( 0.9.7.1-RC1 version )