Hello Onur,
during the import process meteosyn tries to connect to http://maps.solar-software.de/geoservices/FindNearBy/-34.518/-58.467 .
"Missing information could not be imported." occurs when this connection fails (server down, no internet connection, firewall)
Is it possible to open the link in a browser?
Please look for the longitude, latitude and time zone format at http://forum.valentin-software.com/topic/307-is-it-also-possible-to-use-my-own-climate-data/?p=544
Best regards,
Thomas