Qube 6.5 does not have Autodesk 2015 support.
Qube 6.6 does have Autodesk 2015 support.
We strongly recommend an upgrade to Qube 6.6 to get 2015 support. That said, you can modify the job.conf in any of the jobtype dirs to include the paths to 2015, which will at least get 2015 running in Qube. You can also explicitly set the path to the 2015 executable in the submission dialog in 6.5 to run 2015 jobs. *That* said, the 6.6 jobtypes contain bugfixes/improvements that make upgrading worth while.