Kies Air - Fix
I had this same problem, watched Kies connect once, but never connected again, kept stalling. Tried Mozilla, Chrome and Explorer, all with the same result. Then I noticed lots of Java icons stacked up in the taskbar, and under closer inspection, lots of instances of java started in the task manager.
Turns out the problem is the Java cache on your PC, it doesn't clear after you drop the connection, and prevents further re-connection attempts. Uninstall the Java on your PC and it all works fine. Not sure what you need to do if Java is essential to you.
Turns out the problem is specific to Java 6.24 and if you roll back to 6.23 it will be working again