I added 'xls' to the array $wgFileExtensions in LocalSettings.php, and tried to upload a ~20kb spreadsheet.
I get the message: "The file is corrupt or has an incorrect extension. Please check the file and upload again."
I tried uploading several times, and successfully opened the file in MarinerCalc. (I don't do monopolies, so can't check it in Excel, but I'll bet neither can MediaWiki... :-)
The server is case-sensitive; the client is case-preserving. The actual file extension is lower case.
I've done the same procedure with 'pdf' files, and can successfully upload those.
This is MediaWiki 1.5.3, on MacOS X 10.4.5 with MySQL 5.0.15.
Any ideas?
:::: Beware of the military-industrial complex. -- Dwight D. Eisenhower :::: Jan Steinman http://www.Bytesmiths.com