I had tested two plugins for pictures galleries, Easy Gallery and Gallery and both return almost the same error message I have not found any trace around on the FAQ's or so. It happens whenever I try to upload more then on picture at the same time from my computer. It fails and returns a message like "server error. system temp directory (c:\temp\) isn't writable" and no pictures are uploaded.
Here's another example of the problem (WBS Gallery plugin)
Choose an image to upload:
Upload a file
This is my blog, http://www.stefanome.it/blog/
Thank you for your help!