I have the very same problem - even though I selected my printer as the server default one in the CUPS administration interface (web based), LibreOffice still complains it cannot find it : then I click OK and it works until I quit / restart Libo.
Print defaults always to landscape mode - print. I'm using LibreOffice, so things might be slightly different, but I've had this problem before with Calc. Libreoffice landscape printing problem I found, however, a solution thanks to dimesio in the OpenSuse Forum which works for me, and may work for others.
