While trying to install a wordpress theme that was packaged as an .rar archive I got the following error:
The package could not be installed. PCLZIP_ERR_BAD_FORMAT (-10) : Unable to find End of Central Dir Record signature
This is because I’m trying to unpack a .rar archive and the server doesn’t have rar archive support installed, however you can get around this issue quite easily.
All you need to do is unpack the .rar archive and re-pack it as a .zip archive and re-try the upload. Everything will work as expected after that.