25. A method of previewing the generation of a content package file, the method comprising; obtaining references to first level content files from a content package file, wherein the content files are separate filed from the content package file; extracting content from first level content files referred to in a content package file; extracting content from one or more lower level content files referenced to the first level content files; replacing references to the first level content files and the one or more lower level content files with at least some of the extracted content to generate a combined content file representing a modified version of the content package file; removing the references from the combined content file; and previewing the modified version of the content package file to determine if there are issues associated with generating a modified content package file using the combined file content.
25. A method of previewing the generation of a content package file, the method comprising; obtaining references to first level content files from a content package file, wherein the content files are separate filed from the content package file; extracting content from first level content files referred to in a content package file; extracting content from one or more lower level content files referenced to the first level content files; replacing references to the first level content files and the one or more lower level content files with at least some of the extracted content to generate a combined content file representing a modified version of the content package file; removing the references from the combined content file; and previewing the modified version of the content package file to determine if there are issues associated with generating a modified content package file using the combined file content. 27. The method of claim 25 , wherein previewing the combined content file comprises identifying any of the first level content files or any of the one or more lower level content files that overwrite existing files to generate the modified content package file.