Mithcell,

If it weren't for you, I wouldn't have had DNN installed yet! Just following your example and sharing what I learned the hard way!

My first thought on this is you should clear the cached objects, Broadcasts, and Server table. See if the two production servers show up. Then monitor the table to see if the poll date is getting updated. If not, then your cache will continue to grow out of control. Basically, the query that purges the broadcasts table deletes the records older than the minimum last poll date of the servers table. So if your Last Poll dates on your servers are not being updated, then your broadcasts table will keep growing. I believe it is in the broadcastpollingprovider code wher the lastpolldate is updated. I am away from my code so I will have to check into it when I get back to my desk. 

Another item to check is your scheduled task. Make sure it is set to every 30 seconds and is indeed enabled. Ensure that you leave the field blank where you specify which server to run it on so as you run on both.

Maybe the above will get you working. Please let me know if you do or don't.

Sorry for the delay, I have just been trying to think about your situation. One thought of what may be causing some of the server's lastpolldate to not be updating could be related to the site being shut down due to inactivity. If the application is not running on a particular box, then the scheduled task are not running. For more information on the ASP.net worker process and its effect on DNN, please go to Mitchel Sellers great blog post:

By default IIS will shut down the ASP.NET worker process after 20 minutes of inactivity meaning that the next request will restart the worker process and cause the compilation to occur.

http://www.mitchelsellers.com/blogs/articletype/articleview/articleid/103.aspx

So, one question I have is whether or not you are experiencing traffic on all of the servers? Can you view the site log and see if the application is shutting down at all? You might want to have a keep alive to rememdy.

Also, your posted on the following thread ( http://www.dotnetnuke.com/Community/Forums/tabid/795/forumid/108/threadid/178701/scope/posts/Default.aspx ), that the broadcastpollingprovider is not keeping your files in sync. I do not think that is a function of the provider. The provider is handling cache. You might try running the syncronize files option in the file manager checking the recursive box once the files have been transfered. I don't really know if that will fix the problem you are describing, but it is worth a try.

Hopefully this will give you some things to try. Good luck!