Symptoms
When try export projects from FPP files you may get the following exception:
(Exception) TargetInvocationException: Exception has been thrown by the target of an invocation. at FluentPro.OfficeInterop.Helpers. COMAction.CallWithRetry(Func`1 func, Int32 retryCount, Int32 retryDelay) at FluentPro.OfficeInterop.MSProject.MSProjectApplication. FileSaveAs(String fileName, PjFileFormat format) at FluentPro.FluentBooks.WizardControllers. UploadProjectsFromFppFilesWizardController. UploadProject(PSDataProvider provider, MSProjectApplication app, List`1 destinationCustomFieldNames, List`1 destinationNativeFieldNames, List`1 destinationTaskCustomFieldNames, List`1 requiredFields, ProjectInfo project) at FluentPro.FluentBooks.WizardControllers. UploadProjectsFromFppFilesWizardController. UploadProjectsData(AuthenticationType authenticationType, String url, String login, String password, ServerType serverType) (Exception) COMException: An unexpected error occurred with the method.
Cause
The issue can be caused by losing resources in the project. You may see them as apparent material resources in the resource sheet with no name, or in the Gantt you see numbers where you expected to see names – and similarly they are material resources in the resource form. This issue happens due the bug in Project Professional. The detailed description of this bug can be found in the article below (see Reference).
Workaround
The workaround for this problem is already implemented in FluentBooks. When FluentBooks runs into the issue with blank resources during uploading fpp-files, it automatically attempts to replace them with Enterprise Resources with type 'material' and names “Invalid Resource 01”, “Invalid Resource 02” etc, in case such Resources exist in the target PWA. So all you need is to create such Resources using Resource Bulk Edit Wizard.
Reference