SORRY m_s!
I really shoud have informed myself before saying anything.
here's the solution for your problem (i think):
hotkey,SC174,down
hotkey,SC175,up
return
down:
Send,#&{PgDn}
return
up:
Send,#&{PgUp}
return
It seems that for creating a hotkey with VK/SC, this syntax has to be used.
Basically, on the first part, you declare the hotkeys, then, when each of one is pressed, the program goes to the label that it's designed to go.
Very sorry to have caused you so much stress..