[Mediawiki-l] Problem uploading certain files (blank upload form)

[Arne Bittig]

Hello everyone,

I am running a wiki for a research project with access restricted to the 
participants. So far, it works quite well, but there is a problem with a 
file upload.

When trying to upload a certain .ppt file, the data seems to be sent to 
the wiki (according to the browser's progress bar), but when it should 
be finished, all I (as well as the contributor whose file it actually 
is) get is a blank upload form. However, this only occurs when I try 
this from home. When I'm at work, i.e. in the same local network as the 
server the wiki is on, I get to the file's description page, and the 
file is shown correctly in the file list (which it is not in the former 
case).

Even more confusingly, uploading different .ppt files (smaller as well 
as larger ones) seems to work fine from everywhere, as is the case with 
other file types (e.g. pdf). But when I convert the ppt file mentioned 
above to pdf (using StarOffice), the result will not be uploaded 
correctly either.

I am aware of the advice given at 
http://meta.wikimedia.org/wiki/Uploading_files#I_get_a_Blank_Screen_.28IE.29_and_a_Blank_Upload_Form_.28FireFox.29_after_uploading_an_image, 
but it was not helpful in my case.

MediaWiki version is 1.6.7 (I set it up a while ago, and it was hardly 
ever used since; futhermore, the server, on which I do not have admin 
privileges, has only PHP 4.3.4).
The relevant lines in my LocalSettings.php are
$wgEnableUploads    = true;
$wgUploadPath       = "$wgScriptPath/img_auth.php"; #"prevent not 
logged-in users from accessing files
$wgUploadDirectory  = "$IP/files";
$wgCheckFileExtensions = false;
$wgStrictFileExtensions = false;
$wgUploadSizeWarning = 8 * 1024 * 1024;
$wgVerifyMimeType = false;

In the php.ini, memory_limit is 64M. I also tried 
$wgMimeDetectorCommand= "file -bi" as described on the page linked 
above, but on solaris (afair), the file command seems to work slightly 
different, and since $wgVerifyMimeType is false anyway, this should not 
have any effect, should it?

Thanks in advance,
Arne