Writing XMP data to PDF does not work

JabRef 5.0-alpha
Windows 10 10.0 amd64 
Java 11.0.4-bellsoft

Steps to reproduce:

1. select entry
2. Tools > Write XMP metadata ...
3. Error 

Paste your log details here.

<details>
<summary>Detail information:</summary>

```
Writing XMP-metadata...
Finished writing XMP for 0 file (0 skipped, 1 errors).
```

</details>