The .docx Word and .xlsx Excel file formats are not supported within QuarkXPress 8.12 and lower. We are in the process of adding the ability to import the new Microsoft file formats of .docx, .xlsx, etc. in an upcoming release of QuarkXPress.
To import the content from a .docx document, the best solution is to down-save the file in Microsoft word from .docx to .doc, .rtf, or .txt and import the down-saved file. If down-saving is not an option, the file can be opened in MS Word and the text can be copied and pasted from the document into a QuarkXPress text box. This option allows the text to be imported, but may not always bring in the correct text and paragraph formatting.