I tried all three settings in my appSettings and the error was the same everytime.  Each time it appered the uploader was able to write file to the temp directory but then when clicking save I get the error.

 

I commented out all the code in the save button hander and error did not occur. So then I started adding things back in to see when the error would occur. Checking if the page IsValid made it happen as well as trying to create a new directory to save the temp file in.

 

Let me know if you have any other suggestions.