Hello LL Data Dawg,
This is slightly hasty as I'm multi-tasking, so please forgive me if I'm completely wrong, but it might be worth searching the forums for "printer driver" as there's a known issue which might be causing this.
Essentially, if you change your default printer driver back to something simple (Microsoft Generic Text printer driver, for example) you may find Excel exports behaving themselves again.
In order to bring data from an Excel into Monarch, you must open the file as a Database source instead of a Report source (File -> Open Database...), using Monarch Pro.
Then follow the wizard through and you should be OK.
Er, hold that thought. If you're having trouble reading the Excel files that are exported by Monarch, go to the Options -> Export and Clipboard... dialog, and set the Excel driver to "Excel 97+ (Monarch v8)".