The curse is: on one side of the scroll is written that every theif will be banished, on the other side is written that every one who swears falsely will be banished. That these two sins will ruin the household where the liar and theif live. The scroll was a writing that was rolled from each end toward the center. These were common in the early days even after christ. Zechariah was a prophet and was given visions pretty specific for the people of Judah. These were warnings for them to turn away from their sinful ways and turn back to God. If they didn't there would be consequences, such as the destruction of the households where the liars and theifs lived. It still has relevance for us today in that if we donn't walk away from our linful life we will suffer the consequences.
Does that make sense?