Fatal Error: Call To Undefined Function Geoip_country_code_by_name() When Clicking On My Site From Yahoo Search Results I Get A Fatal Error Message But Just With Yahoo.?

When clicking on my site from Yahoo search results I get a fatal error message but just with Yahoo.? - fatal error: call to undefined function geoip_country_code_by_name()

Fatal error: Call to undefined function: iconv () in / home / content / c / y / / / canadianmale html / tr ... on line 412
I have no problem with other search engines, only Yahoo. I have never seen this error before. Ideas?