Got error "Version mismatch with vmmon module: expecting 304.0, got 279.0." after upgrading to 7 from 6 when trying to start up my ubuntu vm guest

Please help: I just updated my MacBook Pro to OSX Yosemite and at the same time I upgrade VMWare Fusion 6 to Fusion 7. Everything looks good. Then, I try to startup my Ubuntu vm (which worked fine prior to Yosemite and Fusion) and get the following error:

Version mismatch with vmmon module: expecting 304.0, got 279.0.

It is critical that I am able to bring back my Ubuntu vm as it is my development workstation.

Thanks