RFL200859: Import of a previously exported project file in XML form not possible

Issue Description
 
In some rare situations, it is not possible to import a previously exported project file (in XML format). This issue is caused by invalid database entries, that reference different projects.
 
Solution
 
To rectify the problem, follow the steps outlined below. These steps ensure, that the exported XML files do not contain invalid entries, that cause issues by subsequent import operations.
 

1. Download the attached SQL script
2. Access your database management tool with appropriate administrative privileges.
3. Select the database, that is used by the project, to be exported.
4. Create a backup of your database before proceeding with any modifications. This step ensures that you can revert to the previous state if necessary. 
5. Execute the SQL script provided with this article. 
6. Once the database is fixed, export the source project to the XML format.
7. Now you will be able to import the exported file from step (6).