colouring with layers

I'm very new to Photoshop and finding it very difficult compared to other graphic packages. My question is probably really basic but I can't figure it out
I have a drawing in one layer, and want to colour it in in another layer. However, nothing happens when I use the paint bucket tool, because the outline isn't there, although it works fine in the layer with the original drawing. I was told to select the areas I wanted in the layer with the drawing, then switch to the new layer and colour in, but that didn't work either though it worked for the other person. I'm using Photoshop v6.0.1. How can I make this work??

use ALT+BACKSPACE to fill selections.
Put the coloring-layer´s mode to "HUE" or "COLOR"

thanks, I noticed that it wasn't working because I had imported a file from flash, which made the background white rather than transparent, so I just wasn't seeing the changes.
Which leads to my next question. Is it possible to save an image made in flash with transparency intact, so that it can be used in photoshop with layers? I tried saving as gif, as that was the only format which allowed me to preserve transparency, and then converting it to all three formats where photoshop allows you to use layers. None of them worked - I couldn't add more layers. Is there any way round this, or will I have to make my original image in photoshop in future?

I'm not sure if I understand you right, (That's probably my problem more than it is yours) but I think you can copy the image from its uneditable state to a new editable psd. Your steps would be as follows. (CTRL+A, CTRL+C, CTRL+N, [enter], CTRL+V). Now you should be able to add as many layers as your version of Photoshop will allow.

that works, thanks