Hi Logan, and welcome to the VMware Communities!
Fusion 5.0.5 is too old to work with OS X 10.10. Apple have been steadily improving the security around the use of kernel extensions, and those included with Fusion 5.0.x (which was designed to work with OS X 10.8) do not meet the requirements of OS X 10.10. There are probably many other compatibility issues beyond that one, but that is specifically what's causing the failure you are seeing.
To resolve the problem, you'll need to upgrade your copy of Fusion.
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Darius