Setup RAMBo board

Guys, I am having problems setting up a Rambo board on my 3D Printer, this is genuine board I paid lots of money for not a cheapie! System is Windows 10, COM6, Arduino has RAMBO set as board 301, no problems so far.

Every time I try to upload I get the following message

Warning: Board Arduino_1.x.x:rambo:mega2560 doesn't define a 'build.board' preference. Auto-set to: RAMBO_MEGA2560 recipe.preproc.macros pattern is missing

Error compiling for board RAMBo.

So what does this mean and how can I fix it??

Looks like the core you're using was meant for 1.0.6, and hasn't been updated for 1.6.x? Contact the manufacturer for updated core, or go back to the IDE version they recommend.