The inability to access files created with earlier versions of ClarisWorks is usually caused by a damaged "XTND Translators List" file; a file that ClarisWorks creates and uses whenever you open or import a document. Follow these steps to trash the old translator file and create a new one:
1. Quit ClarisWorks.
2. Open the Preferences folder within the System Folder.
3. Drag the XTND Translators List file to the trash.
4. Launch ClarisWorks. ClarisWorks will then check the translators in your system and create a new XTND Translators List file.