There is a limitation on supported bit width with our current implementation. So what you need to do is to reduce the bit widths of your program. You might want to check out Computation With Quantized Functions — Concrete Numpy Manual to find out how to do it.
In a nutshell, you could reduce the number of bits necessary to carry out the computation without losing much information. Quantization can become handy in such scenarios and if you want to learn more about it you can read Quantization — Concrete Numpy Manual.
And, for further releases, we are working to support larger bit widths in the Concrete library.