Fasttext exception error
You are probably trying to load word vectors that are shared in the fasttext.cc website or are trying to load using models that are trained with the latest one on master. There is an issue in github with a lot of comments. One solution is to try to load from the text files the code for which is given here. I was able to work around this using java but had to train it in java only. Take a look at the examples in this package.

https://github.com/vinhkhuc/JFastText/tree/master/examples/api