OK, that error message is what you would get if you supply a string (in quotes) when the function is expecting an integer (a whole number). It probably refers to your line 'lcd.print(":");'. Now, maybe the member function 'print()' of the object 'lcd' simply doesn't support character strings for some reason? And you need to use a different member function? Is there a 'println()' function? The example code from the Playground seems to use 'printIn' (with an 'I'):
#include <LCD4Bit.h>
LCD4Bit lcd = LCD4Bit(1); //create a 1-line display.
lcd.clear();
delay(1000);
lcd.printIn("arduino");
Is that example correct?