Hi, usually this happens when some wrong value is entered like a text value in Date or Number field.
Also this error happens when you trying to insert value into auto-increment field or some NOT NULL field left empty etc. Double check everything I mentioned and if it doesn't help post your application to Demo Account (last tab in ASPRunnerPro).
Send me a URL where I can see this issue. Also I need a step-by-step instruction on reproducing this error.