Try looking at your settings for "Scratch Disks" where there are a half dozen settings that tend to be remembered from project to project. If on previous project PrE used your SD card, it may still be wanting to continue to do so.
Edit > Preferences > Scratch Disks..
What version of Premiere Elements are you using and on what computer operating system is it running?
If Windows 7, 8, or 8.1 64 bit, please follow the route to the Adobe Premiere Elements Prefs file to delete or disable it. If that does not work,
then you delete the whole folder in which it exists
Local Disc C
number of version that you have Folder
and in that Folder will be the Adobe Premiere Elements Prefs file that you delete.
Be sure to be working with Folder Options Show Hidden Files, Folders, and Drives enable so that you can see the complete path cited.
If you are a Mac user, I believe the path is
Libraries\Users\Owner\Application Support\Adobe\Premiere Elements\number of version that you have\
I am strictly an Elements Windows user, so that is not a first hand route.
What is in the computer's SD card slot at the present time?
What is shown in the new project dialog's Save In field (See File Menu/New/Project) or the Save In field when you use Publish+Share/?
Let us start here and then we can decide what next if necessary.