[UserNameGoesHere]

My guess (and I could be wrong) is it's some sort of lag? It could even be something like your antivirus software or firewall interfering with the game somehow.

Do you have any other programs open/running at the same time you're playing? How much RAM do you have? (Subtract some if your graphics card or onboard graphics uses system RAM rather than its own RAM)

Try: Disabling or uninstalling any toolbars and/or plugins and/or addons except for Flash. Turning off any "auto-update" features in any software you may have and just remember to manually update every so often (once a week or two is good). Disabling any unnecessary servers and/or services (google to see what's needed). You might need to configure your antivirus and/or firewall software as well.