I don't think that guy stole your pano using print screen. I doubt this is even possible.
Let's say you have a cube mapping panorama and you are looking at the front face. When you see it in krpano it looks ok, but the actual source image is deformed.
This is because the corners of the square are further away than the center of it, thus the corners will appear smaller than the center. To compensate for this, the actual image must be stretched out a little to the corners. I think more troublesome to steal a panorama using print screen. I doubt you would get the same quality.

Unfortunately he can actually steal your panorama jpg files
Step 1. You have a html that is embedding a swf. He views the source and finds the name of the swf ... and the name and path of the main xml file for the panorama.
Step 2. He gets the xml file by adjusting the url to point to the xml file.
Step 3. He analizes the main xml file and sees you are doing some loadpano(somefile.xml)
Step 4. Again, he makes a request and gets this new somefile.xml where he can see you are doing <image type="CUBE"> or something like that. There, in plain text is the path to your image files
Step 5. Hooray, he makes a request for the panorama jpg file by adjusting again the url to point to those images.

if you that worried, change all of your images to .mov, and put a watermark IN the jpg before converting to .mov :) krpano can use .mov files no problem, and this way even if they find the .mov they will have to convert it back (not so hard if you know where to look) but if you put a watermark its going to be useless to them unless they want to promote you :P

Hi,

disabling the system print screen is impossible,
but what you could do would to encrypt the images with the kproect tool, then downloading and using them would be not possible,

best regards,
Klaus