Can't enter MS Office serial number in wine?

Make sure you haven't overridden riched20 library.

That library must be overridden in wincfg as "Native (Windows)" for correct operation of the applications of the Office suit, but must not for the Office setup.

After the complete setup and/or serial key (if inserted after instalation), re-enable the riched20 library override.

Thanks to rygar:
http://ubuntuforums.org/archive/index.php/t-1283792.html