Here's what works for me.
Right click on any file and select Properties. Under the General tab click on the Attributes check box until it is blank. Click Apply then OK. That file should no longer be read only.
You can do the same thing for all the files in a folder at one time by right clicking on the folder and doing the same steps above. This works for your Documents folder as well.
By the way, I switched from Open Office to LibreOffice a number of years ago because I had the impression that Open Office wasn't being updated any more. Give LibreOffice a try.