Sometimes, an error like this is displayed in the WP Dashboard when trying to update the plugin “The package could not be installed. PCLZIP_ERR_BAD_FORMAT (-10) : Unable to find End of Central Dir Record signature”. This error message is commonly related to a hosting setting.
When updating the plugin your website has to connect to our servers in order to download the latest version. However, some hosting company block CURL calls which causes the error message.
The solutions are:
1) You may get in touch with your hosting provider and ask them to make sure that CURL is installed and not blocked.
2) You can login to your BUP account and download the latest version to your local disk, then upload it by using the WP Plugins link.
3) Download the complement, unzip it and upload the Booking Ultra Pro Complement folder via ftp to your plugins folder.