LCD hookup and programming

I have been working with the arduino and have been having troubles with interfacing it with an LCD 5v from sparkfun.

my problem is set up the lcd with 4 and then 8 bit using the LCD header file and cpp files in the hardware libraries.

LCD pin1 GND LCD pin2 5v LCD pin3 10k pot from pin2 LCD pin4-pin6 RS-RW-E LCD Pin7-14 Datalines LCD pin15-16 LED Back light

my problems start by just pluging the thing in. the Contrast only works correct if I plug the thing to ground. I don't this this is right. The pot should be on the voltage side?

The only thing that I have been able to get out of the thing is it sets and then boots and then it displays two four blocks

XXXX - full blocks XXXX

Does anyone have an idea as to what is going on?

Thanks

What exact model are you using? Are you using the lcd4bit or the liquidcrystal library? Tie pin 5 to ground. See if that helps.

Thanks what the pin 5 all about?

You can read data from the lcd or something. If not needed, just ground the pin and it works.