no text on LCD

[skimask]

i have a 4x20 line lcd display with a program to say hello world.
when the program is run it just shows up as a small block in the top left corner
when the capacitors each side of the crystal are removed (2 x 33nf) it shows up as 2 lines of blocks
can some one tell me why it is doing this and not displaying my text?

Code? 1-2 second pause after startup to let the LCD startup? Contrast voltage is obviously set ok.