As a user of a Unix Swiki server and Mac browsers, I've not experienced
any problems that others seem to be reporting with uploading.
It would seem that a more enhanced form of collaborative debugging would
be helpful in isolating this problem. In particular, it'd be good to know
where in the process things are failing.
I don't know where to start, but perhaps it would be possible to annotate
the uploading code to print some verbose logging to a file. From those
logs, it may be easier to find the idiosyncrasies of the different
browsers.
I'll see what I can come up with,
-Eric