godamuss wrote: I have avast anti-virus installed
You need to completely uninstall Avast AntiVirus in order to get VMware Workstation to install. This has been a problem of late and seems to be the only solution when current Avast products are installed. After VMware Workstation (or Player) is installed you can reinstall the Avast product.
While you're at it you should file a complaint with Avast for not having a way to allow a legitimate products, like VMware products are, to be installed without the complete removal of the Avast product! 