Installation reports that archive extraction has failed and stops installing, although the unzipped dir is OK

Reported by Samuel GOUGEON (@sgougeon)

BUG DESCRIPTION:
----------------
When installing scilib_geo from scratch (no former installation or scilib_geo dir in SCI/contrib), the download is OK but then an error message is displayed 
 * in console:  atomsExtract: The extraction of the archive 'C:\PROGRA~1\scilab\SCILAB~1.2-2\contrib\scilib_geo\scilib_geo_0.5.59.1-1.bin.zip' has failed.
 * in a message box: Installation failed!

Yet, when going to SCI/contrib, the unzipped scilib_geo_0.5.59.1 directory is available with its files.
Then, the list returned by atomsGetInstalled does not show scilib_geo, even after restarting Scilab.

ERROR LOG:
----------
atomsExtract: The extraction of the archive 'C:\PROGRA~1\scilab\SCILAB~1.2-2\contrib\scilib_geo\scilib_geo_0.5.59.1-1.bin.zip' has failed.

HOW TO REPRODUCE THE BUG:
-------------------------
atomsInstall scilib_geo
atomsGetInstalled