Try repairing disk permissions. That can fix a myriad of bugs.
Quit any open applications/programs. Launch Disk Utility. (Applications/Utilities) Select MacintoshHD in the panel on the left, select the FirstAid tab. Click: Repair Disk Permissions. When it's finished from the Menu Bar, Quit Disk Utility and restart your Mac. If you see a long list of "messages" in the permissions window, it's ok. That can be ignored. As long as you see, "Permissions Repair Complete" when it's finished... you're done. Quit Disk Utility and restart your Mac.
Try the Dictionary widget... if it still won't work ... You could trash the old one and reinstall from your Mac install disk.
I assume the Dictionary widget you are using, or trying to use, is the one that comes pre-installed?
If so...
To reinstall applications that came with your Mac:
Insert the Mac OS X Install Disc and double-click the package that installs bundled software or additional software. A package has an icon that looks like an opened box.
Follow the onscreen instructions. If you see a pane with a Customize button, click Customize and select the application you want to install. If you see a pane that lets you choose what to install, click the disclosure triangle beside Applications and select the application you want to install.
If you can’t find the application you’re looking for, you may need to reinstall Mac OS X. Your documents and user settings will remain.
Insert the Mac OS X Install Disc and double-click the Install Mac OS X icon. In the pane where you select the destination disk, select your current Mac OS X disk, and click Options. Select “Archive and Install” and “Preserve Users and Network Settings.”
🙂