First stop playing with this chargers with your zaurus, if you do not know what are you doing, you may burn your zaurus.
1.- You need at least a 5 volts (5.4 v will be ok) in order to charge your zaurus battery.
2.- You need an AC -DC convertor at least of 800mA.
3.- You need to know if the DC output is really clean. Because if you see the output of a nokia charger it is a sine wave up to 10 volts, i have a LG littium cell phone charger , DC very clean (5.2 v - 800mA).
4.- Connect with the right polarity, for the c700 is correct (+ inside, - outside)
5.- I do not recomend (it is my opinion) the usb charger for the c700 it consumes a little more than 500mA and your usb can burn. I made a usb charger and connected the c700 to a external hub with a external supply and the Regulator of the usb hub gets a little hot.