Your browser does not seem to support JavaScript. As a result, your viewing experience will be diminished, and you may not be able to execute some actions.
Please download a browser that supports JavaScript, or enable it if it's disabled (i.e. NoScript).
After the last hotfix, the trades are no longer possible. When you ask someone for trade, he receives a notification. If he accepts, the windows will open for him, but not for the one proposing the trade.