Were you able to access it before?
Which language version of CS4 are you using?
Yes I was able to access it before, i'm not sure what happened, maybe some update that I later installed either for the Creative Suite or for some other app messed with the Kuler installation. I guess I could reinstall my suite but I'm not sure what sort of impact that would have on my updates. I'm using the English version, US based.
Are you on Win or Mac?
Can you check if following folders are present on your hard drive and are not empty?
C:\Documents and Settings\<user>\Application Data\Adobe\CS4ServiceManager\extensions\KulerPanelBundle\
C:\Program Files\Common Files\Adobe\CS4ServiceManager\extensions\kuler\
Hello Sonika, I actually reinstalled CS Suite along with Windows, so everything's working fine now, but thanks for the tip and I'll make sure to check if anything like this happens again.