I ran into a problem when transferring large numbers between the client and server. They would send me a number and when I sent it back to them it would be different. Turns out ActionScript 3 has problems with big numbers. Here is a quick example. The expected output would be 129090238754375001.
var string:String = "129090238754375000";
var number:Number = Number(string);
var nextNumber = number + 1;
Here are the variables after execution. Notice that both number and nextNumber are 129090238754375008.
And the output window:
The solution in our case was that, since we were not doing any math and just using it as an identifier, we changed the server code to use a string instead.