Cannot open documents via doubleclick. must navigate thru folders

Question

I am helping an elderly gentleman. Suddenly he finds that doubleclicking on an Appleworks document does not open it. He has to navigate through the Finder-which is slower and confuses him.
IF he reboots his Mac (iMac 17") everything again is ok and he can simply double click..
But then the problem returns and he cannot open the documents again unless he reboots.
Not sure what triggers the problem-it is not a corruption as the problem clears when reboot. Unless some sort of temporary cache or permission is involved?
Slight suspicion this is related to updated Fax software but not sure. (PageSender)
Has anyone had similar problem? Any known application conflicts?
Responses welcome ... and Happy Holidays

Answer 1

A couple of things might help. Whenever you do an update, & installing software can fall in this category, it's a good idea to do two maintenance tasks, one for the system (Repair Permissions) and one for AppleWorks (delete preferences). (Thanks to Barry for this way to format this very common answer.)
To Repair permissions in 10.4.x, launch Disk Utility, found in the Utilities folder in your Applications folder, click on First Aid, then on Repair Permissions.
To delete AppleWorks’ preference files, go to HD > Users > Library > Preferences. Find and delete the file com.apple.appleworks.plist. Find and open the folder AppleWorks in this Preferences folder, then delete all of the enclosed files (with the exception of the Button Bar Preferences if you have customized the Button Bars). AppleWorks will recreate the preference files as it needs them.
Partly because AppleWorks 6 is actually an OS 9 application carbonized to run in OS X, there can be some confusion between AppleWorks files & OS X because pre-OS X systems don't use file extensions.
Sometimes, merely "telling" OS X that AppleWorks is to open these files will work. Click a known AppleWorks document in the Finder to highlight it & choose Get Info from the File menu. In the Get Info box, click the triangle next to "Open With." Click on this drop-down menu & choose AppleWorks 6. If AppleWorks 6 is not a choice, choose "Other" & navigate to the AppleWorks 6 application. Now click the "Change" button under the text that asks if you want to open all documents like this with AppleWorks 6.
If that doesn't work consistently, you can add the .cwk extension to the file names. This user tip explains how you can add the extension to whole folders of files at a time.