Ringrazio ancora per tutti i consigli... ho sostituito i PPR0 con PPR in ports.cpp però mi da questi errori:
C:\Documents and Settings\Santo_ale\Desktop\arduino-1.0\libraries\LibHumidity\LibHumidity.cpp:27:20: error: wiring.h: No such file or directory
C:\Documents and Settings\Santo_ale\Desktop\arduino-1.0\libraries\LibHumidity\LibHumidity.cpp: In constructor 'LibHumidity::LibHumidity(uint8_t)':
C:\Documents and Settings\Santo_ale\Desktop\arduino-1.0\libraries\LibHumidity\LibHumidity.cpp:39: error: 'OUTPUT' was not declared in this scope
C:\Documents and Settings\Santo_ale\Desktop\arduino-1.0\libraries\LibHumidity\LibHumidity.cpp:39: error: 'pinMode' was not declared in this scope
C:\Documents and Settings\Santo_ale\Desktop\arduino-1.0\libraries\LibHumidity\LibHumidity.cpp:40: error: 'LOW' was not declared in this scope
C:\Documents and Settings\Santo_ale\Desktop\arduino-1.0\libraries\LibHumidity\LibHumidity.cpp:40: error: 'digitalWrite' was not declared in this scope
C:\Documents and Settings\Santo_ale\Desktop\arduino-1.0\libraries\LibHumidity\LibHumidity.cpp:42: error: 'HIGH' was not declared in this scope
C:\Documents and Settings\Santo_ale\Desktop\arduino-1.0\libraries\LibHumidity\LibHumidity.cpp: In member function 'uint16_t LibHumidity::readSensor(uint8_t)':
C:\Documents and Settings\Santo_ale\Desktop\arduino-1.0\libraries\LibHumidity\LibHumidity.cpp:114: error: 'class TwoWire' has no member named 'send'
C:\Documents and Settings\Santo_ale\Desktop\arduino-1.0\libraries\LibHumidity\LibHumidity.cpp:115: error: 'delay' was not declared in this scope
C:\Documents and Settings\Santo_ale\Desktop\arduino-1.0\libraries\LibHumidity\LibHumidity.cpp:124: error: 'class TwoWire' has no member named 'receive'
C:\Documents and Settings\Santo_ale\Desktop\arduino-1.0\libraries\LibHumidity\LibHumidity.cpp:125: error: 'class TwoWire' has no member named 'receive'
Un po di errori li ho risolti cercando su internet il file wiring.h (presa da: http://arduino.googlecode.com/svn-history/r22/trunk/core/wiring.h )e mettendolo nella cartella LibHumidity.. Ora lanciando la verifica mi scrive:
C:\Documents and Settings\Santo_ale\Desktop\arduino-1.0\libraries\LibHumidity\LibHumidity.cpp: In member function 'uint16_t LibHumidity::readSensor(uint8_t)':
C:\Documents and Settings\Santo_ale\Desktop\arduino-1.0\libraries\LibHumidity\LibHumidity.cpp:114: error: 'class TwoWire' has no member named 'send'
C:\Documents and Settings\Santo_ale\Desktop\arduino-1.0\libraries\LibHumidity\LibHumidity.cpp:124: error: 'class TwoWire' has no member named 'receive'
C:\Documents and Settings\Santo_ale\Desktop\arduino-1.0\libraries\LibHumidity\LibHumidity.cpp:125: error: 'class TwoWire' has no member named 'receive'
Che abbia sbagliato libreria LibHumidity?! 
Grazie
Ale