Error Caught in Application_Error event

Error in: https://www.investore.io/en/detalle-estrategia.aspx?RXN0cmF0ZWdpYQ=MTE4&RXhwZXJ0bw=MTI2&cHJvdmllbmU=buscarn&desde=SinLogin&imp=10000&desc=1
Error Message: Conversion from type 'DBNull' to type 'Double' is not valid.
Stack Trace: at Microsoft.VisualBasic.CompilerServices.Conversions.ToDouble(Object Value, NumberFormatInfo NumberFormat) at Microsoft.VisualBasic.CompilerServices.Conversions.ToDouble(Object Value) at CalcRendimiento.posicion_un_dia(String fechap, String idcliente) in C:\Inetpub\vhosts\investore.io\httpdocs\App_Code\CalcRendimiento.vb:line 206 at CalcRendimiento.gananciaPeriodo(String idestrategia, Int32 dias) in C:\Inetpub\vhosts\investore.io\httpdocs\App_Code\CalcRendimiento.vb:line 64 at detalle_estrategia.detalle_estrategia() in C:\Inetpub\vhosts\investore.io\httpdocs\en\detalle-estrategia.aspx.vb:line 787 at detalle_estrategia.detalle_estrategia_InitComplete(Object sender, EventArgs e) in C:\Inetpub\vhosts\investore.io\httpdocs\en\detalle-estrategia.aspx.vb:line 160 at System.Web.UI.Page.OnInitComplete(EventArgs e) at System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint)