Keep getting an error after creation of the first question.

Error: Survey is currently unavailable.
DotNetNuke.Services.Exceptions.ModuleLoadException: Input string was not in a correct format. ---> System.FormatException: Input string was not in a correct format. at System.Number.StringToNumber(String str, NumberStyles options, NumberBuffer& number, NumberFormatInfo info, Boolean parseDecimal) at System.Number.ParseInt32(String s, NumberStyles style, NumberFormatInfo info) at System.String.System.IConvertible.ToInt32(IFormatProvider provider) at System.Convert.ToInt32(Object value) at DotNetNuke.Modules.Survey.SurveyController.GetSurvey(Int32 SurveyID, Int32 ModuleId) at DotNetNuke.Modules.Survey.Survey.lstSurvey_ItemDataBound(Object sender, DataListItemEventArgs e) at System.Web.UI.WebControls.DataList.OnItemDataBound(DataListItemEventArgs e) at System.Web.UI.WebControls.DataList.CreateItem(Int32 itemIndex, ListItemType itemType, Boolean dataBind, Object dataItem) at System.Web.UI.WebControls.DataList.CreateControlHierarchy(Boolean useDataSource) at System.Web.UI.WebControls.BaseDataList.OnDataBinding(EventArgs e) at System.Web.UI.WebControls.BaseDataList.DataBind() at DotNetNuke.Modules.Survey.Survey.DisplaySurvey() at DotNetNuke.Modules.Survey.Survey.DisplaySurveyPage() at DotNetNuke.Modules.Survey.Survey.Page_Load(Object sender, EventArgs e) --- End of inner exception stack trace ---

Any clue?

KOM2