There is a particular way that fonts are searched for in Scribus, and the spelling of the fonts is specific. If the spelling of the font changes, Scribus will think it's missing when an old file is loaded.
Here is a bug filed on this: http://bugs.scribus.net/view.php?id=7098 I think the process you should go through is this: In Scribus, look in File > Preferences > Fonts to make sure these fonts were found by Scribus when it started up. If not, you may need to run fontconfig to find them. When you load the file, Scribus should tell you it wants to substitute for a "missing" font. Use the drop-down list to find the font you wish. Alternatively, go through your document and correct the fonts. Make sure you save your file after you make the fixes, otherwise you will go through this again the next time you load this file. It's not clear why they keep changing names in freetype2, but this probably isn't the last time. Greg
