The problem you have described was detected and fixed in the Q2 2010
release of the RadControls. Most probably your version of the RadControls is older than that, so I would recommend updating them to the latest release in order to remove the issue and to experience the new features that have been added.
If you are unable to upgrade, you can try the following workaround - the CSS provided below should be placed in your page's head section:
.RadColorPickerRTL .rcpIcon em
I hope the information, listed above helps. Feel free to contact us again should you need further assistance.
the Telerik team