Lpc2000

Currently I have an LPC2129 and am trying to use the P0.2/SCL and 
P0.3/SDA/Eint1 pins for GPIO.

Running the software under simulation in KEIL shows the micro correctly 
changing the states of these pins however once applied to the physical 
chip on a board we've designed in house there's no signal - basically  
ground with a little noise. I've been over the schematics (as I didnt 
design this board) and there appears to be nothing obviously wrong. 
However given both of these pins are potentially used for I2C I was 
wondering if they additionally need pull-ups but I can't see anything 
anywhere in the errata etc to explicitly say they do...

Anyone had a similar problem with these particular pins? (I'm using 
P0.4, P0.5 etc for the same form of output to drive relays and they're 
all working fine).