If you receive that error, then it means it's wrong associated or the file is corrupted, but I believe it's a simple association error. Locate the file then right click it and choose Open With. From the dialog window that will open, choose Adobe Reader or Adobe Acrobat and accept the changes. You also have to tick the option to always open the file using one of the selected PDF applications and then it should open correctly. If you still have issues, reinstall/repair the applications on your computer.