Remove Velocity errors in logs when displaying the main page on the default wiki

15:43:46,761 ERROR P1-19 http://localhost:8080/xwiki/bin/view/Main/ SimpleLog4JLogSystem:logVelocityMessage:154 - Left side ($category) of '==' operation has null value. If a reference, it may not be in the context. Operation not possible. Main.WebHome [line 5, column 16]
15:43:46,783 ERROR P1-19 http://localhost:8080/xwiki/bin/view/Main/ SimpleLog4JLogSystem:logVelocityMessage:154 - Left side ($velocityCount) of '==' operation has null value. If a reference, it may not be in the context. Operation not possible. Main.WebHome [line 48, column 42]