I have found out how to add a scroll bar to the infolog.
The div containing the infolog has the class dynInfologOuter. If you edit the AXEP.css file to add:
max-height: 120px;
overflow-y: scroll;
... to the .dynInfologOuter css class, the infolog will add the scrollbar and display all the error messages in that height, and the 110px allows for 5 errors to show up.
This, however, will change the infologs everywhere in Enterprise Portal, which isn't necessarily a bad thing to have them all like this.