[Zope] System variables

Hi, I import a Web Site with hundreds of pages into Zope. Every pages use the folder "icon" for images. As I create a folder with the name "icon", a error message came from Zope. --> Error Type: Bad Request Error Value: The id icon is invalid - it is already in use. I think "icon" is a system-variable. My Question: Is there any possibility to create this folder? Thanks.