Continuity mistake: When Rowan is stabbed by Jason she slides down to the floor and freezes sitting up. She remained undiscovered and undisturbed for over 400 years until the scientists find them. So how did she end up lying on her back covered up by what look like exhaust tubes? Aside from the unlikelihood of no-one stumbling across her for all that time.
brianjr0412Continuity mistake: In the fight scene between Jason and Kay-Em, she's blasting away at him with the auto-guns. When Jason falls, you see that his machete is almost bloodless, but a second later, it's bloodied up again.
Movie Nut
Chosen answer: There is a certain difference between filling out paperwork and preparing a chamber for cryogenic freeze. Rowan may have reserved the cryo chamber for Jason, filled out the forms and put his tag on it, but she had yet to prep it properly (check that every detail was in working order, maybe run a test, re-check, etc). So there may have been a tag on the chamber with the name "Vorhees" on it, Rowan just did not think of this as "prepping".
Twotall