What you are looking at is what salesforce calls a GACK: A gack is our blue screen of death, our frowny Mac icon, our “the number you have reached is no longer in service”, our “Jedediah has died of dysentery”. A gack is what happens when an error got thrown within our application and we didn’t catch it and handle it.
What this means is that it’s not your fault. It’s ours. That’s why we apologize in that message. Sorry!
This friendly message is the above-water portion of a huge iceberg of functionality. The numbers you see are part of an elaborate system for efficiently bringing these events to the attention of R&D.
Its time to log a case with support when you encounter the gack !