importing psd error

This problem just popped up for me. I've been going back through my book and doing some fine tuning, which means that I either select all the files and delete them or I delete the page and re-import the psd file. I don't use the import option without deleting all of the elements because it always messes up all the layers.

The last few times I've done it, when I select the import psd file option it brings up the calculator and won't let me import the file. I close the program and try it again, sometimes it lets me do it and sometimes it brings up the calculator again.

Sometimes the old layers come in instead of the new ones unless I shut the program down and start it again.