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Solution 3 (not recommended):
Turn off WHOIS option in configurations (menu->JoomlaStats->Configuration->Whois option)
Remember that JoomlaStats will be unable to find country for some visitors.
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FromJoomlaStats version 3.0.x you don't get an error message is whois can't connect on port 43. If you are using JoomlaStats 2.3.x or before you would have seen "Warning unable to connect to x.x.x.x 43".