While I never thought いえ vs いいえ can ever be a problem, I have noticed many of my students have trouble hearing いえ (house) and いいえ (proper “no”) apart. In order to hear them apart, try pronouncing them apart. In order to say いえ, you need to keep the い sound really short. Please listen to the difference: 

いえ

このいえがすきですか。

いいえ

いいえ、すきじゃないです。