IS it safe to delete wow64 dll's when autoruns says so?

That's a windows Black Magic (TM): http://answers.microsoft.com/en-us/windows/forum/windows_8-performance/wow64dll-wow64cpudll-wow64windll-files-not-found/837ba758-ad0a-4bc3-b227-62046f7e198d?msgId=762f85e0-f11f-481b-a0e8-b92971acf422

Don't be concerned if autoruns reports these files as not found. Just ignore it. These three files are critical to (and invisible to) 32-bit processes running on a 64-bit processor.

For a little fun you can see this by launching both the native and x86 versions of Windows PowerShell, type the following in both. Somewhat surprisingly you'll get different results:

cd $env:windir\system32
dir wow*

It is not safe to delete those dll files. Those listed files supports 32 bit applications running in 64 bit machine.Instead of deleting dll files try to register dll by typing
regsvr32 /s wow64win.dll in command propmt with administrator privillege