Exception while compiling: wrong version 50.0, should be 49.0

The library you’re using was compiled with Java 6
Your compiler is Java 5 that’s why it doesn’t understand that format.
To fix it you have to get a 1.5 version of the library or upgrade your compiler to 1.6 I suggest the later.

http://stackoverflow.com/questions/1766216/exception-while-compiling-wrong-version-50-0-should-be-49-0