fyi:
use a shielded cable (i use normally a standard "printer" cable db25/db25,
1:1 pinout, 1,8mtr) and make sure, that you connect the shield at the end
where the lcd is connected to ground. that normaly fix all glitches and
pixelerrors (i use several lcd's, 128x64, 122x32, two different 240x128).
I use a shielded printer cable, too but my problem is that I do not have
exclusive access to the printer port :-(
There is always some activity on some data lines (0,1,2,4 I think) even if
there is no process that accesses the port.