Hi,
Pi4 recognization was improved and thus libIDs have changed.
Here are your options:
1. Contact us via
support@jdownoader.org
2. Wait for the soon coming RARv5 update.
3. Use these libs:
mega.nz/file/7A9GgAyL#HVq2FgluXhXmNV4pbb3Mc6phEPQCgE4EwRke6CNGkn0
-psp-