Unable to use a weapon on the second check for Nualia

So I was using Valeros, against Nualia in the warrens location. After the first check, she rolled for damage again. Also I was not able to use a weapon again during the second check. I was on normal difficulty, and the only scenario power was the one that made the check to aquire items or weapons increased by 2.

Would there has been a reason I couldn't use a weapon on the second check, and also, is there a reason she did damage before the second check even though I did do the check on the first time.