message: Add NPE troubleshooting tips
diff: @@ -41,3 +41,14 @@ Then run
  #### Troubleshooting
  Use environment variable `RUST_LOG={info|debug|trace}` to output logs of Libindy.
  +
  +If your application that uses libindy crashes with a Null Pointer Exception then probably the libindy shared library could
  +not be loaded properly. If you have build libindy from source then either put the resulting shared library where your
  +operating system searches for shared libraries or set appropriate environment variables to help the OS's loader to find them.
  +
  +On Ubuntu either copy libindy.so to /usr/local/lib or set LD_LIBRARY_PATH to the directory that contains libindy.so.
  +
  +```
  +export LD_LIBRARY_PATH=<path to libindy.so>
  +```
  +
  