You could try turning off the hyperlinking option I guess, but I have students who use a similar combination (they use either Word 2003 or 2010, X5 and Win7 or WinXP) who don’t experience this problem (and believe me, they would complain to me). I am not sure how many use the short-cut. Is it only when you use the short cut this happens?
To turn off hyperlinking (which my students don’t like, because they don’t like the citations printed in blue, anyway) open the reformat bibliography (the "bibliography dropdown at the bottom of the endnote ribbon) and untick the box. You can always turn it on again later, if it is a feature you want in your final document.
There are a few things that can slow down the Cite While You Write process enough to cause a time out. The most common are the Cite While You Write Option to "link in-text citations to references in the bibliography and Word’s Track Changes.
-The linking to the bibliography does just that. It adds a hyper-link over the hidden field codes of each reference that points to the bibliography. Most people don’t use this and it can add significant time if the document is large.
This can be turned off in Windows by going into Word and pressing ALT+3. This should bring up the Format Bibliography window with the setting. Unchecked it and press OK.
-Track Changes in Word keeps track of changed text without actually removing the old text. It seems like this is also happening with the field codes that are hidden in the back ground of formatted references. Most often, just keeping Track Changes in Final mode, rather than Final Showing Markup, when working with Cite While You Write is all you need to do.
If the document’s field codes are already corrupted and putting the document in Final mode doesn’t help, you should call Tech Support as they should still be able to help you.