I downloaded "LCD1602.rar", expanded it, expanded LCD1602/LCDKeypad.zip and moved the resulting LCD1602/LCDKeypad folder to Arduino/libraries/LCDKeypad. When I compiled the "GuessTheNumber" example (File->Examples->LCDKeypad->GuessTheNumber) the first error I got was:
Arduino/libraries/LCDKeypad/LCDKeypad.cpp:5:22: error: WProgram.h: No such file or directory
That indicates that the library was not updated for Arduino 1.0. I changes "WProgram.h" to "Arduino.h" and the example then compiled just fine.
I did NOT install the "LCD4Bit_mod" library because the keypad example uses the built-in "LiquidCrystal.h".