[GNC] Can't get v3.8 to work, Nor generate Expense Over Time Report on v2.6.21

[LEO BOLTA]

Greetings,
I could not get the latest 3.8 update to work at all, so had to uninstall and go back to the earlier stable version of 2.6.21.  Unfortunately, I don't recall the version that I was using before trying to upgrade to the latest but I believe it was possibly 2.6.18?  The version 2.6.21 works almost flawlessly but cannot generate the report "Expenses Over Time" and only get a "Report Error - An error occurred while running the report" message.

I should also mention that for some time now, while running my older version (2.6.18?) and the current (2.6.21), I continuously get an error message like the one below on each start-up of the program: 

"GnuCash could not obtain the lock for file://C:\Users\Ownerà\Desktop\GnuCash.gnucash.  That database may be in use by another user, in which case you should not open the database. What would you like to do?"
I have always chosen the option to "Open Anyway", to get started in using the program.
Any help to get the latest 3.8 version working and the program being able to generate my favorite Expense Over Time Report would be much appreciated.
Leo