Hello,
Would like to inform you that even the trial version of Fusion is 100% complete software. There is no any limitations or feature flaws in the trial version. It is as the actual software itself. Regarding the crashes please go to virtual machine settings >Display >and turn off the 3D acelatration. Ensure that while you are doing this the virtual machine should be turned off. For more info please go through this trail :
http://blogs.vmware.com/teamfusion/2012/11/macbook-air-and-macbook-pro-update-2-0-and-vmware-fusion-5.html