Hypersmurf said:Fail to activate, you mean?
If you fail to activate the scroll (unless you get a mishap, which can't happen with UMD anyway), nothing happens... the scroll is not expended. You can try again next time you have a standard action available (or whatever the activation time of the scroll is).
-Hyp.
The only restriction on trying again is if you roll a 1.
SRD said:Try Again: Yes, but if you ever roll a natural 1 while attempting to activate an item and you fail, then you can’t try to activate that item again for 24 hours.