Most likely, you are formatting with an output style that doesn't include a citation definition, such as the "Show All Fields" output style or the "Chicago 15th A" output style. To fix this, format the bibliography with a different output style.
To reformat with a different output style:
Go to Tools > EndNote submenu, and then select Format Bibliography. From the EndNote tab, click the bottom corner arrow.
In OpenOffice.org Writer, go to the EndNote menu and select Format Bibliography.
In the drop-down output style list, select the output style you would like to use. A generic output style you can use for this purpose is the "Author-Date" style. You can click the Browse button to choose from other available output styles.
Click OK to format the document using the selected style.
If you are using an author/year type of output style, and the reference you are citing does not include an author or a year, there will be nothing to display in the citation. The citation will not show up, although the full form will appear in the reference list at the end of the document.