Error-correcting codes provide a technique for enhancing the accuracy of optical matrix-vector multipliers (OMVM's). The effects of signal-independent and signal-dependent noise on the performance of OMVM's that employ error-correcting codes are studied through the use of computer simulations. Noise present in the matrix results in random errors that can be corrected by these codes. Noise present in the vector results in nonrandom errors that are difficult to correct by using random error-correcting codes. The effect of code type is also investigated.