Thanks for the quick reply - I added the line " <add key="CuteEditorTempPath" value="~/uploadertemp" />"
to my web.config, closed the app, reopened it, attempted to upload an image using the ImageGallery link, and got the following response:
Basically, I haven't yet been able to demonstrate in any way that the editor is making use of that AppSettings entry. The debugging process is complicated by the fact that this is being served from a shared hosting environment, but I think that if I could even get to the point of seeing an error reading "Access to path c:\blahblahblah\uploadertemp is denied", I could figure it out from there.
Thanks for your help!