SLCD compile program (Ian McDonald library)

On some computers I cannot compile the example file. However maybe I could just recompile the library as I have the source code. Who could hint me here?
The library and example helps to control SparkFun LCD very easily for at beginner like me


(These are my error messages:)

/Users/ianmcdougall/Applications/arduino-0011/hardware/libraries/SLCD/SLCD.cpp:6
8: undefined reference to `HardwareSerial::print(char)'

/Users/ianmcdougall/Applications/arduino-0011/hardware/libraries/SLCD/SLCD.cpp:6
9: undefined reference to `HardwareSerial::print(char)'

hardware\libraries\SLCD\SLCD.o: In function `SLCD::print(char const*)':

/Users/ianmcdougall/Applications/arduino-0011/hardware/libraries/SLCD/SLCD.cpp:9
5: undefined reference to `HardwareSerial::print(char const*)'

hardware\libraries\SLCD\SLCD.o: In function `SLCD::sendControl(char)':

/Users/ianmcdougall/Applications/arduino-0011/hardware/libraries/SLCD/SLCD.cpp:1
11: undefined reference to `HardwareSerial::print(char)'

/Users/ianmcdougall/Applications/arduino-0011/hardware/libraries/SLCD/SLCD.cpp:1
12: undefined reference to `HardwareSerial::print(char)'

hardware\libraries\SLCD\SLCD.o: In function `SLCD::print(char const*, int, int)'
:

/Users/ianmcdougall/Applications/arduino-0011/hardware/libraries/SLCD/SLCD.cpp:8
7: undefined reference to `HardwareSerial::print(char const*)'

I have the same problem...would love to know what's going on with the compiling.