This is a suggestion to test the users opera config directory:
Option 1) Can a different user, on the same system, using opera, view distrowatch correctly? In other words, try create a new user on the problematic system, and then see if that user can correctly view distrowatch. If they can then perhaps it's just a config directory problem (~/.opera) which should be easy to rectify on your main user account.
Option 2) The other option is, which opera closed, rename your ~/.opera directory to something else (e.g. .opera_old). Then start up opera and see if the problem still persists. If it doesn't then the problem lies somewhere in the opera config directory; if it does then you can close opera, remove the new config directory, and move your .opera_old back to .opera.
There's also the possibility that it's a global configuration setting. I believe that when opera is installed it asks the user where or not to use global preferences which get installed somewhere in /etc, and this is what's presented by default. Perhaps moving these preference files to a backup location and restarting Opera to test (similarly to above) could prove fruitful; if not, then you can put back the original preference files.
Hope this helps, or gets some other ideas going.
One more: Try starting opera from the console and look to see if any messages are displayed (i.e. warnings, errors, missing dependency messages, etc).