Add error when price calculation was not successful

MultiTool.Common/Constants.vb

@@ -81,6 +81,7 @@
         MandatorNotFound
         MissingXmlAttribute
         AttributeValidationFailed
+        PriceNotCalculated
     End Enum
 
     Public Class DocumentError

MultiTool.Common/Documents/DocumentLoader.vb

@@ -383,6 +383,7 @@ Namespace Documents
         ''' </summary>
         Public Async Function MaybeApplyPriceFunctions(pDocument As Document, pMandator As Mandator, pTemplate As Template) As Task(Of Document)
             If pDocument.HasErrors Then
+                pDocument.AddDocumentError(DocumentErrorType.PriceNotCalculated, "Der Preis konnte für mindestens eine Zeile nicht ermittelt werden, weil es noch Fehler im Dokument gibt")
                 Return pDocument
             End If