Many people (me included) have problems with Webroot Secure Anywhere (WSA) interfering with "copy & paste" functionality in some applications.  It's a great program but sometimes it's overly protective.  In this case WSA's Identity Protection module is protecting your clipboard data.  It's easy to restore copy & paste functionaity to WebSite X5 Evo v10:

Open the WSA contol panel.  This is usually accomplished by double-clicking the WSA icon (looks like a little green meatball with a "W" on it) in the Task Bar.

Click on "Identity Protection" to open that module's options in the right side panel.

Click on the gear icon to get into the Advanced Settings.

Click the "Application Protection" tab.

Find "website5.exe" in the list of apps being watched by WSA, and then change the setting to "Allow".

Close the WSA control panel - and that should do the trick.

I've attached a screen capture showing the setting.