lep136:
Problem
row #1 & #3 have all 20 char boxes illuminated
row #2 & #4 have all 20 blank
This is normal for a display that has power applied but has not been initialized properly.
so far I downloaded the LCD4Bit library ...
The original post is 2-1/2 years old and so is the library you mentioned. Try using the latest version of the LiquidCrystal library (Arduino v0017) and see if things work out better.
Don