Reaction of sodium hydroxide with ethanol
The hydroxyl group in ethanol has a pKa of about 16 (see wiki), which means you will not be able to deprotonate it using sodium hydroxide. Thus, the result of your titration should not be altered by the amount of alcohol in the solution.

Depending on the amount of ethanol I could envision that you are not determing solubility in pure water but in the sepcific mixture with ethanol, but that seems to be assumed in this kind of experiment, right ?