Steve did you check the module? All different types of them that I've been using have internal pullups already builtin (Sharp, Picvue, Phillips,...16x1, 16x2, 20x2). It was the same with me at the beginning, that I had a nightmare, but the reason was that the initialization sequence was not right. I did manage to initialize it to 4bit bus mode, but after a warm restart (manual press of reset button of the uC), it was not running any more. The reason was, I did not strictly follow the initialization sequence. I have already installed some 100 devices with no problem for years. I use 8bit shift register so the 8051 interface is with only 3 lines. When LCD module already put into 4bit mode, all the reset AD's are don't care.