hammer.dll not valid windows image

after finding the hl2 engine to be a powerful engine i decided to begin installing the sdk. Now everything runs fine on my home computer but when i get to school and try to run hammer with everything installed like at home it comes up with a bad image error. Im not to sure what this means but hammer doesnt work on any of the computers here. My only guess us because they all run on Windows NT, windows 2000 but i dont think that has that large of impact on the launching of the game. If any1 knows how to solve this problem please help. By the way i did have admin rights when trying to launch the editor, and tried not having admin rights either, that did not work.

How did you try and get to Hammer whilst at school? If you tried to
copy the files across, it might not have worked - that's all I can
think of.