To install the Poodll filter you will need to be able to upload a file of up to 50MB. In new Moodle installations sometimes the file upload limit will be too low. It can be set as low as 2MB sometimes. This is impractical for many uses, and one of those is when installing Poodll.
Moodle sets the upload limit at the Site Security Settings:
site administration -> Security -> Site Security Settings
But usually the problem is that the PHP settings are limiting the upload file sizes. If the highest you can see here is 2MB then its likely you need to change the php settings.
In php.ini there are three settings to check:
Set post_max_size and upload_max_filesize to 100MB or more.Set max_execution_time to 600.
Then restart your web server. Moodle has documentation on this here:https://docs.moodle.org/35/en/File_upload_size