I'm still having the issue! To recap:
Have tried changing profile pic through my viewer. I get an error when I try to upload it direct from my computer, and with viewer 3 there is no way to choose my profile pic from my inventory.
Have tried changing it through my profile online (my.secondlife.com or whatever it is) with two different browsers. Get an error then too.
Yesterday it let me do it and I DIDN'T get the error, but it did not change my profile pic. I.e. I clicked to upload it, it said it had uploaded but the old pic remained. Tried that a few times, still no cigar. Tried deleting my old pic and it still didn't work. Now today I am getting the same errors again both through the viewer and online through browsers.