The MultiSave OK Button in the save multisave documents for any file format (.odt, .doc, .pdf) does'nt work in the dialog after click of multisave icon or by menu extension file/multisave with LibreOffice 188.8.131.52 french version. The extension is Multisave 1.3.0. The Multisave_Ok Sub are stopped at the choixFormat.execute instruction in the LibreOffice.StarXpert_Multisave plug-in macro.
This bug seems to exist from any LibreOffice 4.2 edition.
Seems NOTOURBUG, extension developer should be responsible to keep it updated with latest LO release.
From the following link we can see that extension last updated in Dec 12, 2011 and compatible up to LO 4.0 :
Perhaps this extension is the replacement :