Thanks for your reply! But the changes in the phpThumb.config.php didn't solve the problem. The site still shows only text links or nothing. The links are also not clickable.
You can tweak your installation - edit phpThumb.config.php (refer to phpThumb documentation how), not sure if CL Gallery would need additional tweaking. Just try it and let me know.
Type ...admin_config?[debug=sql,+] in your browser, go to category creation page, submit and see if you are seeing any sql errors reported by e107 at the bottom of admin page.
I see you are using /~guitars/ so I think the URL is apache rewritten. You have to re-set the exact docroot/webroot paths in phpthumb.config.php so that they fit your server settings.