Please, don't put your personal details in your posts. Your email is of no use to us on the forum, so I removed it. Don't want spambots to get a hold of it. ;-)
A screenshot of one of those messages would be nice, so we can know more specifically what we're talking about. I suspect it's the one that allows you to copy some code and urges you to send it to the Support, which usually indicates your network connection problems.
My first suggestion would be to try Google Chrome, if you can. It seems that the devs are using it and, for most people, that's the browser in which the game behaves the best.
Frequent reloads are, unfortunately, a must. I let the game run in my browser non-stop, but I reload every 2-3 hours of active play. I've noticed that visiting havens with lots of improvements, lots of map surfing, viewing garrisons with loads of units (for example Presidios and Bastions),... cause problems. Pretty much anything you'd expect to need a lot of computer memory is a problem. So, when doing any of these, I also reload.
Friend's problems got less severe when he upgraded RAM (computer's memory). I think that 8GiB of RAM is a minimum to be able to play comfortably.
If you want the Support to look into this, there are ways to provide them with more info than just a description. Please, look here. The first link is currently broken, but you don't need it anyway, since you already know how to clear the cache. Look at the rest of that post, especially the "For Firefox users".
Good luck!
