Please elaborate in your situation. What type of connectiona are you using? are you Using LINQ? SQLDataAdapters? or a SQLCommand whith the insert SQL Statement itself?
This sounds like you're not using the correct datatype, sql server supports 'datetime', the datetime type of .NET maps perfectly to this.
Alos if you're setting a default value in SQL server, try removing this particular field from the insert statemnt used in the .NET application that you're building.
Best regards,
Rodrigo Vega