Sorry Kirk.
I'm using PM5 (13507 (c69a93e)) with 10.8.2 on a Intel 2GHZ i7 fitted with 16GB RAM
It happened again Saturday. I had edited 9 images at the previously mentioned 3500px at 300dpi. I pressed Cmd+A then right clicked and selected FTP upload.
I'm wondering if my mobile broadband hadn't quite logged in. I will check and update you shortly
Do you get a spinning beach ball before you see the uploader dialog, or after it appears?
Since you're on Mac OS X, would you mind making a time sample of PM when it hangs and send it to me? You can create a time sample with the Activity Monitor application (Applications/Utilities/). Just run PM 5, run the Activity Monitor, select PM in the list, switch back to PM and start the operation (upload), switch back to the Activity Monitor, and then click on the "Sample Process" button in the toolbar. You can paste it in your reply.
Thanks,
-Kirk