This should do the trick:
Use this script instead of the "dooruse.fpi" script for the door that should start out open and be able to be closed by pressing ENTER.
Remove the state 2 and 3 lines if the door should remain open permanently (Not the most efficient way of doing that, but it's simple and easy).
;Artificial Intelligence Script
; Edited by Plystire
;Header
desc = Use Door (Push Open and Push Closed) Default Open
;Triggers
:state=0:hudreset,hudx=50,hudy=90,hudimagefine=gamecoretextpressentertouse.tga,hudname=usedoorprompt,hudhide=1,hudmake=display,state=10
:state=10,plrdistwithin=60:hudshow=usedoorprompt,hudfadeout=usedoorprompt
:state=10,plrdistwithin=60,plrusingaction=1:activate=0
:state=10,activated=0:state=1,setframe=0,sound=$0
:state=1:incframe=0
:state=1,frameatend=0:state=2,coloff
:state=2,plrdistwithin=60,plrusingaction=1:activate=2
:state=2,activated=2:state=3,sound=$1,colon
:state=3:decframe=0
:state=3,frameatstart=0:state=10,setframe=0
;End of Script
The one and only,
