I'm using SWFUpload with Flash 9 on Ubuntu Linux Hardy Heron in FF3.
Uploading works fine on all other operating systems, but I get an Upload Error: 417 when I try to upload with FF3 on Linux.
Google turns up nothing for SWFUpload, have you seen this error? How can I fix and troubleshoot this.
Not seen this
I have not seen this. The error is originating from your web server (not from SWFUpload specifically). The Flash Player is including an Expects header and the server cannot meet the requirement.
You might do a packet capture to see what Flash "expects" and see if your web server configuration can be updated.