【Unity】can't use image filters (npot-RT are not supported or RT are disabled completely)

can't use image filters (npot-RT are not supported or RT are disabled completely)

ProライセンスではないUnityでImage Effectを使用すると
上記のようなエラーが出るようです

http://stackoverflow.com/questions/15986689/cant-use-image-filters-npot-rt-are-not-supported-or-rt-are-disabled-completely