The same issue happened to me - I only have two add-ins loaded: Amazon Assistant and Roboform Both add-ons are no longer loading. The Assistant shows that it is enabled, but no other information presented. Roboform, when you mouse over it simply displays Can not load plug-ins. When you open extensions the only item is to re-load.
I uninstalled / re-installed Roboform and Opera, albeit the same, most current, versions
Roboform works fine on other browsers
I have disabled my virus scanner / firewall - AVG - software - same issue
A short time ago - an hour maybe - I downloaded, and installed, Adblock Plus, but it is not loading either. When you mouse over the item, it does show Adblock Plus, but when you Manage Extensions, you only receive an option to disable
As it is now three extensions with the same symptoms this seems to point to an Opera, and not Roboform issue.
I use Roboform often - several times a day, so I think I will go back to a previous version of Opera. If anyone has any other options for me - I'm all ears.