In the initial release of pW 4.0, the font settings selected in the pW program settings were not honored (when creating slides for OpenOffice) in some cases - when certain fonts were selected.
This is now fixed as of 1/4/2014. Download and reinstall pW 4.0 to get the fix. You can reinstall on top of your existing install and your database will not be modified, but it is best to backup your data in any case - to be safe.
To backup your data, exit PowerWorship and make a copy of the pwrwsp.sdf file at C:\Documents and Settings\All Users\Application Data\PowerWorship\pW4\Data on Windows XP or C:\ProgramData\PowerWorship\pW4\Data on Windows 7 or Windows 8.