Could Not Set Adobe Elements File Resolution Correctly

I have created a file in Adobe Photoshop Element 6. When trying to set the size of my document to 350ppi, I am having an error stating:
Image Size
A number between 1000 and 256.565 is required. Closest value inserted.
And then it automatically becomes 256.565 but the file became too big. And when trying to edit the file, my computer froze and shows an error
Move command could not be completed as file is too large.
How can I set the resolution correctly?

