[Q] Including roottools error topic

I've done another project that include roottools as explained here: https://github.com/Stericson/RootTools/wiki/Usage, with Eclipse.
I made a new project and I had only include the roottools.jar file.
But when I try to run the program appears this error:

Code:

---

Conversion to Dalvik format failed with error 1.

---

How can I solve this problem?