Open up Console (It's in Applications/Utilities, or runnable via Spotlight).

In Console, go to All Messages in the upper left to show everything at once.

Then launch an Office app and look for relevant errors in the Console log output.

http://www.macobserver.com/tmo/article/mac_os_x_using_console_to_troubleshoot_problems/

This is a pretty standard way to get more info to aid in troubleshooting a number of Mac issues. Similar to looking in Event Viewer in Windows.

Since this specific issue is with Microsoft Office, it should also have come with a Microsoft Update program. Make sure to fire that up and ensure they have the latest updates for Office.