SQL server Conversion failed when converting date and/or time from character string.

Hello i  have  a problem in Sql and VS C# application coding when it begin to save...

this is the code i typed in c# windows application

SqlCommand Cmd = new SqlCommand("insert into table_4 values('" + tb_iTemCode.Text + "','" + tb_iDesc.Text + "','" + tb_iPrice.Text + "','"+tb_Uom.Text+"','" + cB_Config.SelectedItem+ "','"+LblTimer_Date+"')", Con);

and code in SQL server

when i debugg with this codings ... i receive error"Conversion failed when converting date and/or time from character string."

how i do overcome this problem.....