Hi, I encountered his problem also, in my thorough investigation I discovered that the first report (default) usually hello ushahidi) caused the problem.
Delete the first report( Default report)
Select the country in your map setting
Then by the left that show map drag the pointer to your specified country.
I believe your message will show in your map by this method.
I do not believe background image cause the problem
If you have any problem am ready to assist you.
I started using ushahidi from Ushahidi "2.1 Tunis - Official" I have been able to solve any problem encountered during 5years of using it. now am using 2.7.4