Excuse me, but you wrote:
When I click on the buttons to launch the docs from the task bar
This clear states "launch the docs from the task bar". If the documents are loaded, and showing in the task bars, as tasks, then you are simply switching between task. Launch generally means to load.
OK, so you have a bunch of documents open. I can not duplicate you problem. I just tried having seven different documents open, and I can switch between them (using the Taskbar) with no problem at all.
1. How much memory do you have?
2. Do you have other applications open?
3. Are any of these documents opened by code? In other words did some code open these documents, or did you just open them with File > Open, or Windows Explorer?
4. Does this happen all the time, or just once in a while.
5. Does this do similar things with other Office files (Excel for example)?
Gerry