CMYK problem in PS8

I'm having a spot of bother. I'm working on a map and need to put the coastline from 100K to 100C and 50M. However, when I try to paint or fill with this colour, It reverts to 100C and 6M. It worked fine on a file I did yesterday, but now it doesn't.

Any suggestions on how to get the colour I want?

G5 2ghz, 2.5mb, OX10.3.2

Thanks in advance

In the options palette - make sure the opacity of the brush is set to normal.

Thanks Jason

It was set to normal and I've discovered the problem. I had an brightness/contrasat adjustment layer in the wrong layer set that was causing the problem. All is fine and dandy now.

Thanks for the suggestion though.

James