It is most likely that there was some other issue rather than both LCDs being bad.There definitely seems to be an issue as this scenario has shown up more than once lately. My guess, based on very limited information, is that the LiquidCrystal library may not be working reliably with LCD modules that are slower (lower internal clock frequency) than normal. The 8-bit mode seems more tolerant than the 4-bit mode which doesn't surprise me. Perhaps a bunch of these marginal or out-of-spec devices just got dumped on the market.
Well i think it is because my displays are so old! One is a PowerTip 1602f, The other is a Sharp LM16A21. It has a real Hit HD44780A00 Driver chip on it. So i thought it would be perfect. All i did was add the extra 4 data lines, Add the referance to the extra 4 lines in the display setup line in the code and they both started working.
I didn't post any links in the first post. As i was talking about this page (arduino.cc). Here is the link on this page. http://arduino.cc/en/Tutorial/LiquidCrystal
My LCD board is a copy of the layout listed on that page. But to get it working i had to use 8 Bit mode.