I was also having very stressful problems with MultiBit myself. It was the first light wallet I had ever used and recently when trying to move my coins out, I would get an incorrect password error (I was 100% certain my password was correct). Google search showed that others had the same problem and that errors would be fixed in an upcoming patch. The patch never came. It looks like the bugs were too much for their developers. Fortunately I was able to get the coins back by inputting my wallet words into a bread wallet.